The correct answer is:
Marissa and her partner should have won the point since the ball touched the opponent’s hand.
From ITF Rule 24 and the Code, Item 36: While Marissa and her partner were nice to give their opponents the point, according to ITF Rule 24i., “the point is lost if the ball in play touches the player or anything that the player is wearing or carrying, except the racquet.” Furthermore, the Code states that, “a player shall concede the point when a ball in play touches that player.”