Welcome to the forum, mohamed ashraf sayed.
The perfect infinitive (d) is the best answer grammatically, but your answer (a) would commonly be used by a great number of native English speakers.
In my opinion, it's an unfair question in a TOEIC* test.
* The Test of English for International Communication (TOEIC) is "an English language test designed specifically to measure the everyday English skills of people working in an international environment."
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