Given the question: Information:  - Akhenre Setepenre Siptah or Merenptah Siptah was the penultimate ruler of the Nineteenth Dynasty of Egypt. His father's identity is currently unknown. Both Seti II and Amenmesse have been suggested although the fact that that Siptah later changed his royal name or nomen to Merneptah Siptah after his Year 2 suggests rather than his father was Merneptah. If correct, this would make Siptah and Seti II half-brothers since both of them were sons of Merneptah.   - A sarcophagus (plural, sarcophagi) is a box-like funeral receptacle for a corpse, most commonly carved in stone, and usually displayed above ground, though it may also be buried. The word "sarcophagus" comes from the Greek "sarx" meaning "flesh", and "phagein" meaning "to eat", hence "sarcophagus" means "flesh-eating"; from the phrase "lithos sarkophagos". Since "lithos" is Greek for "stone", "lithos sarcophagos" means, "flesh-eating stone". The word also came to refer to a particular kind of limestone that was thought to decompose the flesh of corpses trapped within it.  - Not to be confused with Amun - her - khepeshef , a son of Ramesses II , and Amun - her - khepeshef , a son of Ramesses III. The Egyptian prince Amenherkhepshef was the son of Ramesses VI and Queen Nubkhesbed . He lived in the Twentieth dynasty and was buried in the reused sarcophagus of Twosret , in the reused tomb of Chancellor Bay , KV13 , in the Valley of the Kings , on the west bank of the Nile , in Thebes , Egypt .  - Nubkhesbed (Gold and Lapis lazuli) was an ancient Egyptian queen of the 20th dynasty. She was the Great Royal Wife of Pharaoh Ramesses VI and mother of Pharaoh Ramesses VII, Princess Iset (God's Wife of Amun) and Princes Amenherkhepshef and Panebenkemyt.  - Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO).  - Ramesses VI Nebmaatre-Meryamun (also written Ramses and Rameses) was the fifth ruler of the Twentieth dynasty of Egypt who reigned from 1145 to 1137 BC and a son of Ramesses III by Iset Ta-Hemdjert. His royal tomb, KV9, is located near Tutankhamun's tomb in the Valley of the Kings.  - Iset Ta-Hemdjert or Isis Ta-Hemdjert, simply called Isis in her tomb, was an Ancient Egyptian queen of the twentieth dynasty; the Great Royal Wife of Ramesses III and the Royal Mother of Ramesses VI.  - Usermaatre Setepenre Meryamun Ramesses VII (also written Ramses and Rameses) was the sixth pharaoh of the 20th dynasty of Ancient Egypt. He reigned from about 1136 to 1129 BC and was the son of Ramesses VI. Other dates for his reign are 1138-1131 BC. The Turin Accounting Papyrus 1907+1908 is dated to Year 7 III Shemu day 26 of his reign and has been reconstructed to show that 11 full years passed from Year 5 of Ramesses VI to Year 7 of his reign.  - Tomb KV13, located in the Valley of the Kings in Egypt, was cut and decorated for the burial of the noble Bay of the Nineteenth Dynasty. An ostraca published in the French Egyptological journal BIFAO in 2000 records that Chancellor Bay was executed by pharaoh Siptah. Consequently, Bay was never buried in his tomb. Moreover, no funerary goods were found in the tomb belonging to Bay. It was later reused by Amenherkhepshef and Mentuherkhepsef of the Twentieth Dynasty.    Given the information above, choose from the list below the object entity that exhibits the relation 'sister' with the subject 'amenherkhepshef'.  Choices: - crystal  - iset  - setepenre
The answer is:
iset