Talk:Mission Rewards/@comment-68.119.52.243-20180312013124/@comment-4448946-20180312031433

You know because it's always the same. Every 4th mision reward from a mission is always rotation C.

Defense gives you a mission reward every 5 waves, so you get your fourth mission reward at the end of wave 20, therefore the reward at the end of wave 20 is rotation C. Four mission rewards later at the end of wave 40, it's a rotation C reward, and another 4 mission rewards later at the end of wave 60, oh look, it's another rotation C reward.

Same pattern applies for every other endless mission type. Every 4th mission reward it's rotation C.

Also, there's literally a section on this page that explains it. Seriously, go read the ''endless missions' section up above.