Can one say

a. If you want to do it, you can do it.
b. If you want it, you can do it.
c. If you want, you can do it.
d. If you want, you can.

?

Which means
1. You have the right to do it, if you choose to.
and which means
2. If you really want to do it, you'll manage to do it.

?

Many thanks.