No sooner the minister had heard (1)/ about the accident (2)/ than he rushed to the spot. (3)/ No error (4)

Answer

1

Explanation

No soonerhad the minister/ No sooner did the minister hearwill replace
No sooner the minister had because-
when No sooner comes at the beginning of a sen- tence, we use inverted word order - Aux. V. comes before the Subject.
Look at the examples given below:

Hence, No soonerhad the minister heard/No sooner did the minister hear is the right usage.