Asked by GIANSH GUPTA KHUNDKER · BIRLA BRAINIACS
Answer: B. needn't have
Correct Answer: b) needn't have
Explanation: "Needn't have + past participle" indicates that an action was performed (they did double-check the calculations) but it turned out to be completely unnecessary. "Didn't need to" implies the action wasn't necessary and usually wasn't performed.
Answering after opening this box earns no Practice Points.