Each question has an underlined word followed by four answer choices. You will choose the word that is a necessary part of the underlined word. Harvest

Harvest means the process of gathering ripe crops from the fields. 'Crop' is the necessary part - you literally cannot have a harvest without a crop to harvest. While autumn is when many harvests occur (in temperate regions), and tractors are tools used in harvesting, neither is necessary to the definition. Stockpile is what happens after harvest, not during it. Crop is the essential element.