Given the task definition and input, reply with output. In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it. Your job is to determine which sentence(s) from the passage can be used to search for further information needed to answer the question.

Question: What was the population of Hertford in 1835? Passage:In 1835, Cowper was elected Liberal Member of Parliament for Hertford, a seat he held for the next thirty-three years, and became private secretary to his uncle Prime Minister Lord Melbourne. He was appointed a Groom in Waiting in 1837, and in 1841 served for three months as a Lord of the Treasury under Melbourne, only resuming office five years later as a Lord of the Admiralty when the Whigs returned to power under Lord John Russell. He again held this post under Lord Aberdeen from 1852 to 1855, and in the latter year was made Under-Secretary of State for the Home Department by his stepfather Lord Palmerston when he became Prime Minister. In August that same year he was appointed President of the Board of Health, and sworn of the Privy Council. Four years later he became Vice-President of the Board of Trade and Paymaster General, only serving for a year before Palmerston appointed him First Commissioner of Works.
In 1835, Cowper was elected Liberal Member of Parliament for Hertford, a seat he held for the next thirty-three years, and became private secretary to his uncle Prime Minister Lord Melbourne