Explanation:

Correct Answer is (b).In this sentence, which is a type 3 conditional sentence, adding 'ed' to the adjective 'present' is erroneous. 
This sentence can be written in two ways:
"Had he been present there, he would have put an end to the happenings." or "If he had been present there, he would have put an end the happenings." The option B, therefore, will make a right choice. Hence, the option B is correct.