How many times can classes be nested within a class?

Question

I came across this questions on one of the online Java Tests. The options were 4,5,8 and any number of times.

I have only used one inner class, but have never tried

Answer 1

Hmmm. I know that the online Java test you refer to is a lousy one. Does that count?

(This is the kind of limit that is irrelevant in practical experience. A similarly ridiculously question would be, "What is the maximum length of a function in bytes?")