Initiate would be correct i belive
"which" has a "ch" sound at the end and "with" has a "th" sound at the end
im guessing you wrote in portugese:
<span>"which" tem um som "ch" no final e "with" tem um som "th" no final</span>
The correct answer is
<span>d. The person |who sells souvenirs| is in the lobby.
Without it, the subject "the person" would be very ambiguous and the sentence would not carry any specific meaning.</span>