Answer
There are 3 subshells.
Work Step by Step
Electron states with the same values of quantum numbers $n$ and $l$ form a subshell.
For each $n$, the values of $l$ can be $~~l = 0, 1, 2,...,(n-1)$
When $n=3$, then the values of $l$ can be $~~l = 0, 1, 2$
There are 3 subshells.
