💡 Detailed Explanation
The correct choice is '食べられません' (cannot eat), which is the negative potential form of the verb '食べる' (to eat). Sentence translation: 'Since I ate a lot of cake, my stomach is already full and I cannot eat anymore.' The other choices are: '食べさせません' (causative negative: do not make/let eat), '食べません' (simple negative: do not eat), and '食べさせられません' (causative-passive negative: cannot be made to eat).