Answer:
D. He knows that helping his brother is more important than collecting cards.
Step-by-step explanation:
Jerry already had two Grover Cleveland cards and while he would have wanted to own an Abraham Lincoln card, he recognised his brother's need.
His brother needed money and even though Jerry was still relatively young, he made a mature and responsible decision to put his brother's need above his. Jerry put aside his need for card collection and instead sold his prized Grover Cleveland card so he could help hs brother with some money.