Chinese Tset: What does “哥们儿 (gēmenr)” mean here?

Beginner Level 初级 (chūjí)
Conversation:
         Gēmenr, xiàwǔ dǎ lánqiú ba.
 Mike: 哥们儿，下午  打 篮球    吧。
         Méi wèntí.
 Tom: 没   问题。
What does “哥们儿 (gēmenr)” mean here?
 A. older brother
 B. younger brother
 C. buddy
See Answer at:
http://resources.echineselearning.com/chinesetest/chinesetest-chinese-465.html?ecl=ptEEEEEpg082201