In Sūrat al - Mā'ūn(Q.107), we learn that a good believer should not

A.

assist in wrongdoing

B.

tell lies

C.

repulse the orphan

D.

harm a fellow Muslim

Correct answer is C

Qur'an 107
[In the Name of Allah, the Most Beneficent, the Most Merciful.]
1) أَرَأَيْتَ الَّذِي يُكَذِّبُ بِالدِّينِ
[Have you seen him who denies the Recompense?]
2) فَذَٰلِكَ الَّذِي يَدُعُّ الْيَتِيمَ
[That is he who repulses the orphan (harshly),]
3) وَلَا يَحُضُّ عَلَىٰ طَعَامِ الْمِسْكِينِ
[And urges not on the feeding of Al-Miskîn (the needy),]