Which of these fruits is not classed as a drupe?

A grape is not a drupe, it is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus 'Vitis'.

In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part surrounds a single shell (the pit, stone, or pyrena) of hardened endocarp with a seed (kernel) inside.

The definitive characteristic of a drupe is that the hard, lignified stone is derived from the ovary wall of the flower. In an aggregate fruit, which is composed of small, individual drupes (such as a raspberry), each individual is termed a drupelet, and may together form an aggregate fruit. Such fruits are often termed berries, although botanists use a different definition of berry. Other fleshy fruits may have a stony enclosure that comes from the seed coat surrounding the seed, but such fruits are not drupes.

Typical drupes include apricots, olives, loquat, peaches, plums, cherries, mangoes, pecans, and amlas (Indian gooseberries).