An action in a sentence can be represented in two ways, namely active and passive voice.
The passive voice always uses the past participle form of the main verb irrespective of any tense. Only the auxiliary verbs depend upon the sentence given in the active voice.
The correct answer is D)He is known to me.
Option D is correct as the given sentence is in the active voice and to transform it into the passive voice the subject of the given sentence (I) comes in the place of the object(him) and vice versa. Also, as the given sentence is in the simple present tense.
Options A,B, and C are wrong as the preposition (by) cannot be used here, the given sentence is not in the simple past tense, and the tense used is not same as in the given sentence.