On a game show, Elena is given the choice of three doors: Behind one door is the Grand Prize; behind the others, consolation prizes. She picks Door A, and the host, who knows what is behind each door,

On a game show, Elena is given the choice of three doors: Behind one door is the Grand Prize; behind the others, consolation prizes. She picks Door A, and the host, who knows what is behind each door, opens Door B, revealing a consolation prize. The host then offers Elena the opportunity to change her selection to Door C. What should she do?