Please answer the following question: Information:  - OpenBSD is a free and open source Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Research Unix derivative developed at the University of California, Berkeley. In late 1995, Theo de Raadt forked it from NetBSD. Besides the operating system as a whole, the project maintains portable versions of many subsystems, most notably OpenSSH, which are available as packages in other operating systems.  - MINIX 3 is a project to create a small, highly reliable, and functional Unix-like operating system. It is published under a BSD license and is a successor project to the earlier MINIX 1 and MINIX 2 operating systems.  - Linux (pronounced or, less frequently) is a Unix-like computer operating system assembled under the model of free and open-source software development and distribution. The defining component of Linux is the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. The Free Software Foundation uses the name GNU/Linux to describe the operating system, which has led to some controversy.  - Ports collections (or "ports trees", or just "ports") are the sets of makefiles and patches provided by the BSD-based operating systems, FreeBSD, NetBSD, and OpenBSD, as a simple method of installing software or creating binary packages. They are usually the base of a package management system, with ports handling package creation and additional tools managing package removal, upgrade, and other tasks. In addition to the BSDs, a few Linux distributions have implemented similar infrastructure, including Gentoo's Portage, Arch's Arch Build System (ABS), CRUX's Ports and Void Linux's Templates.  - FreeBSD is a free and open source Unix-like operating system descended from Research Unix via the Berkeley Software Distribution (BSD). Although for legal reasons FreeBSD cannot use the Unix trademark, it is a direct descendant of BSD, which was historically also called "BSD Unix" or "Berkeley Unix". The first version of FreeBSD was released in 1993, and today FreeBSD is the most widely used open-source BSD distribution, accounting for more than three-quarters of all installed systems running open-source BSD derivatives.  - pkgsrc ( package source ) is a package management system for Unix - like operating systems . It was forked from the FreeBSD ports collection in 1997 as the primary package management system for NetBSD . Since then it has evolved independently : in 1999 , support for Solaris was added , later followed by support for other operating systems . DragonFly BSD , from release 1.4 to 3.4 , used pkgsrc as its official packaging system . MINIX 3 and the Dracolinux distribution both include pkgsrc in their main releases . There are multiple ways to install programs using pkgsrc . The pkgsrc bootstrap contains a traditional ports collection that utilizes a series of makefiles to compile software from source . Another method is to install pre-built binary packages via the pkg_add and pkg_delete tools . A high - level utility named pkgin also exists , and is designed to automate the installation , removal , and update of binary packages in a manner similar to APT or yum . pkgsrc currently contains over 16000 packages ( over 20000 including work - in - progress packages maintained outside the official tree ) and includes most popular open source software . It now supports around 23 operating systems , including AIX , various BSD derivatives , HP - UX , IRIX , Linux , Mac OS X , Solaris , and QNX .    What object entity has the relation of 'license' with the subject 'pkgsrc'?   Choices: - bsd license  - free software  - open source
A:
bsd license