When did the Holy Spirit appear in the form of a cloud?
Explanation:
The Holy Spirit at Jesus' Baptism
The Holy Spirit is mentioned to have appeared in the form of a dove during the Baptism of Christ, not as a cloud. This event is recorded in the gospels of Matthew, Mark, and Luke and is described as occurring when John the Baptist baptized Jesus in the Jordan River. It is during this moment, at Jesus' baptism, that the Holy Spirit descends in the shape of a dove and a voice from heaven declares Jesus as God's Son.
Therefore, the correct answer is c) At Jesus' baptism.