Given the following context:  William Etty was born in 1787 in York, the son of a miller and baker. He showed artistic promise from an early age, but his family were financially insecure, and at the age of 12 he left school to become an apprentice printer in Hull. On completing his seven-year indenture he moved to London "with a few pieces of chalk-crayons in colours", with the aim of emulating the Old Masters and becoming a history painter. Etty gained acceptance to the Royal Academy Schools in early 1807. After a year spent studying under renowned portrait painter Thomas Lawrence, Etty returned to the Royal Academy, drawing at the life class and copying other paintings. In 1821 the Royal Academy exhibited one of Etty's works, The Arrival of Cleopatra in Cilicia (also known as The Triumph of Cleopatra). The painting was extremely well received, and many of Etty's fellow artists greatly admired him. He was elected a full Royal Academician in 1828, ahead of John Constable. He became well respected for his ability to capture flesh tones accurately in painting and for his fascination with contrasts in skin tones. Following the exhibition of Cleopatra, Etty attempted to reproduce its success, concentrating on painting further history paintings containing nude figures. He exhibited 15 paintings at the Summer Exhibition in the 1820s (including Cleopatra), and all but one contained at least one nude figure. In so doing Etty became the first English artist to treat nude studies as a serious art form in their own right, capable of being aesthetically attractive and of delivering moral messages. Although some nudes by foreign artists were held in private English collections, Britain had no tradition of nude painting, and the display and distribution of nude material to the public had been suppressed since the 1787 Proclamation for the Discouragement of Vice. The supposed prurient reaction of the lower classes to his nude paintings caused concern throughout the 19th century. Many critics condemned his repeated depictions of female nudity as...  answer the following question:  What is the last name of the person who exhibited 15 paintings at the Summer Exhibition in the 1820s?
A:
Etty