(something) is not an option
The phrase "___ is not an option" means that you can't do something. For example:
I have a two-year-old and an infant, so flying is not an option.
This means that the speaker can't fly on an airplane because dealing with two young children on the plane would be too difficult.
A common phrase that you may hear is:
Failure is not an option.
People who say this mean that they must succeed at something.