What is can find in the following sentence:

You can find properties of science in a basic clock.

A. Main verb
B. Helping verb
C. Both
D. Neither

I say it is C Both, is this right?

Right!

Yes, you are correct! In the given sentence, the verb "find" serves as the main verb, and the verb "can" functions as the helping verb. Therefore, both a main verb and a helping verb can be found in this sentence. Well done!