Natural Class Question ???

[j4mes_bond25]

I'm asked this question, which I fear is bit beyond me. Can anyone help perhaps explaining what exactly is being expected from this question and/or any answer/help towards it ???

"Is there a natural class that has nasals and approximants but not vowels?? I'm stuck on a phonology problem where one allomorph occurs before a vowel, and another allomorph occurs before nasals and approximants. Sonorants doesn't seem to fit."

Any help would be greatly appreciated.

[Tdol]

I'm afraid it's beyond me too.

[Claire Redfield]

hey guys

take it easy