Detailed Instructions: 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.
Problem:Question: Was the Social Democratic Party around when Knochel was conscripted into the Imperial Army? Passage:Wilhelm Knochel was born into a Social Democratic working class family in Offenbach, a short distance upriver from Frankfurt. He qualified and worked as a factory machine operator ("Dreher"). In 1917 he was conscripted into the Imperial Army, shortly after which he was badly wounded. There are also references to his having worked as a mines maintenance engineer ("Grubenschlosser"). In 1919, with Germany affected by acute economic hardship and, especially in the cities, a succession of revolutionary uprisings, Knochel joined the Social Democratic Party ("Sozialdemokratische Partei Deutschlands" / SPD). By 1920 he had relocated in search of work to the industrially vital and internationally critical Ruhr region. Sources differ over whether it was in 1920 or 1923 that he switched to the recently created Communist Party. Between 1924 and 1930 he was a member of the party leadership team for the Dortmund region ("...des Unterbezirk Dortmund"). In 1930, following the death of his first wife, he returned to Offenbach, where it was arranged that his daughter should be brought up by relatives. Knochel was now employed as a party official.

Solution:
In 1917 he was conscripted into the Imperial Army, shortly after which he was badly wounded