How to show/hide options from a multiple choice option

On my form I have a dropdown that asks for their state.

Then I have a multiple choice question with (a) (b) (c) (d)

When they choose California, i only want options (a) and (b) to be available in the multiple choice question.

Is this possible?

That is not possible. There is no way to disable an option within a Multiple Choice field based on a condition. What you can do is to create each option in a single field, and then disable the field through conditions: https://www.jotform.com/help/371-How-to-Enable-Disable-Fields-Using-Conditional-Logic