"Are you wiping?"
From what I've learned this past year, the translation of "we are wiping" is 'tunafuta' and the translation of "you [all] are wiping" is 'mnafuta.' "You are wiping" (singular), is 'unafuta.' I chose to use the singular form of 'you are...' for this exercise and it was marked correct.
The different conjugations will slowly but steadily make more sense as you work through the exercises. Happy learning!