The correct option is C The seed is the edible part of the fruit.
The cashew tree (Anacardium occidentale) is a tropical evergreen that produces the cashew nut. The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the cashew apple. The drupe develops first on the tree and then the pedicel expands to become the cashew apple. Within the true fruit is a single seed, the cashew nut. The edible part of cashew nut fruit is the seed.
Thus, the correct answer is option C.