Given the following context:

Bennett was born in Sheffield, Yorkshire, the third child and only son of Robert Bennett, the organist of Sheffield parish church, and his wife Elizabeth, née Donn. In addition to his duties as an organist, Robert Bennett was a conductor, composer and piano teacher; he named his son after his friend William Sterndale, some of whose poems the elder Bennett had set to music. His mother died in 1818, aged 27, and his father, after remarrying, died in 1819. Thus orphaned at the age of three, Bennett was brought up in Cambridge by his paternal grandfather, John Bennett, from whom he received his first musical education. John Bennett was a professional bass, who sang as a lay clerk in the choirs of King's, St John's and Trinity colleges. The young Bennett entered the choir of King's College Chapel in February 1824 where he remained for two years. In 1826, at the age of ten, he was accepted into the Royal Academy of Music (RAM), which had been founded in 1822. The examiners were so impressed by the child's talent that they waived all fees for his tuition and board.Bennett was a pupil at the RAM for the next ten years. At his grandfather's wish his principal instrumental studies were at first as a violinist, under Paolo Spagnoletti and later Antonio James Oury. He also studied the piano under W. H. Holmes, and after five years, with his grandfather's agreement, he took the piano as his principal study. He was a shy youth and was diffident about his skill in composition, which he studied under the principal of the RAM, William Crotch, and then under Cipriani Potter, who took over as principal in 1832. Amongst the friends Bennett made at the Academy was the future music critic J. W. Davison. Bennett did not study singing, but when the RAM mounted a student production of The Marriage of Figaro in 1830, Bennett, aged fourteen, was cast in the mezzo-soprano role of the page boy Cherubino (usually played by a woman en travesti). This was among the few failures of his career at the RAM. The Observer wryly commented, "of the...

answer the following question:

What is the last name of the person whose duty was as an organist? 

Bennett