Answer:
Letter d. The Thai restaurant serves a curry dish with rice, vegetables, and coconut milk; a mixed vegetable dish including carrots, broccoli, and squash; and a shrimp dish with mushrooms, squash, and other vegetables.
Step-by-step explanation:
I believe the smartest hint to follow here is to pay close attention to the conjunctions! (The 'a's and 'and's that connect the dishes).
e.g.: The first 'a' presents us the first dish: The curry dish with rice vegetables and coconut milk. - The 'and' right before the coconut milk reveals that it's the dish's last element! And the next 'a' reveals that a new dish will be presented now!
Moreover, one could get confused whether what comes next ('a mixed vegetable dish including carrots, broccoli') is a new dish or a better description of the Curry one - which is letter b's answer. Well, this could be discarded by considering that the word 'dish' appears and this new one has ingredients that didn't appear on the previous one! So a new dish is being presented, the mixed vegetable.
Finally, the best grammatical devices to differentiate ingredients from dishes would be comma for ingredients and semicolon for the latter.