Last Weekend Victor Helped His Sister Move into Her New

Multiple Choice

Last weekend Victor helped his sister move into her new apartment. He didn't really feel like helping her, but he wanted to put her "in his debt," because he is planning to ask her if he can stay at her place for a couple of weeks. By helping his sister move, Victor was thus apparently engaging in ____.

A) egoistic helping
B) altruistic helping
C) zero-sum helping
D) non-zero-sum helping