The correct option is
A He was looked up to by everyone.
The given sentence is in the active voice, as the subject 'Everyone' performs an action 'looked up to' against the object 'him'.
If this sentence is changed to passive voice, then the subject, verb and relevant elements are also changed, in order to retain the meaning of the sentence.
'Subject (Everyone) + verb (looked up to) + object (him)' changes to:
'New subject (He) + verb (was looked up to) + by + new object (everyone)'
The
passive form of 'looked up to' in he simple past tense is 'was looked up to'.
This can be seen in option A, hence it's the right answer.
Option B: The sentence is in present tense whereas the original sentence is in past 'was looked up to'.
Option
C: The preposition 'to' is missing, without which the meaning of the phrasal verb is incomplete. You look up 'to' (towards) someone. Also, 'looked up' has a different meaning 'to find information about', which is irrelevant here.
Option D: The verb 'looks up' is in simple present tense as opposed to the tense of the sentence (simple past). Also, 'to' is missing.
Hence options B, C and D are incorrect.