Which of the following is NOT a trig function OR an inverse? a COT b TON c SIN d COS

B

Step-by-step explanation:

A nice way to remember the normal trig functions and what they stand for is with SOH CAH TOA, where S represents the Sin, C represents the Cos, and T represents tan. Note: those are only abbreviations of the actual words.

I don't know a way to remember the names of the inverse trig functions, but they are Csc, sec, and cot.

Looking at all of the options, only TON does not fit the bill, so that's the answer.