"wish" sentence

[Rustamsher]

I wish I ... on holiday with you, but I am very busy tomorrow.

(a) went
(b) could go
(c) will go
(d) would have gone

I believe (c) and (d) are 100 % incorrect. As regards expressing future wish, both the past
form of the verb (as in (a) ) and modals + bare infinitive (as in (b) ) are used.
Also, my teacher told me that I had to eliminate (a) because the 'past' element does not work with the next part of the sentence, which is essentially a 'present' statement with a 'future' element. Nevertheless, I am in a dilemma between (a) and (b). Which option is intended answer OR is it a flawed test?

Many thanks..

[Alan]

(A) is structurally sound but absurd, since the if-clause would refer to a wish concerning a regular activity, not one specifically related to a future time (tomorrow).

Thus (b) is the only sensible option.