Engine: Expired / Engineering Safety

1. A having undergone a major conversion and has been completed before December 31, 1979
2. B the delivery of which is on or after June 10, 1975
3. C for which the building contract has been placed after December 31, 1975
4. D having undergone a major conversion for which the contract was placed between June 30, 1974 and December 31, 1975

Tip: press A-D to answer