Detailed Instructions: Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.
Problem:Context : Works No. 174 started a modernization programme for the ZSU-57-2 in parallel with the beginning of its serial production in 1957, but this programme was rejected due to the development of new radar-guided SPAAGs armed with small-bore autocannons and another tracked chassis.
Answer : 1957
Solution:
What was the year ZSU-57-2 entered service?