Angiogram pointed at ACA which does supply mesial frontal lobe, medial parietal lobe, caudate nucleus, and genu of the corpus callosum (all of these were answer choices)

ACA does not supply the posterior limb of the internal capsule 

Posterior limb of internal capsule is supplied by the anterior choroidal artery, a branch directly off of the ICA 

However, the anterior limb of the internal capsule is supplied by the ACA via one of its branches called the recurrent artery of Heubner, and also gets some supply from the lenticulostriate branches from the MCA