The correct answer to this question is alternative B) "civilian efforts to aid the war effort in practical ways."
During war, trade is compromised, and the priority for the food supply produced by farmers is the troops, which can cause shortages for civilians. On top of that, attacks on farm lands as well as casualties caused by the war in work forces, also deepen food shortages.
HomeGardens help families provide food for themselves, in a way they depend less on the crops that have been compromised by war. It helps them overcome food shortages.
I would say 'civilian efforts to aid the war effort...' as farm production would primarily go to the military leading in food shortages elsewhere. Growing food at home will lessen shortages for that family, and allow them to trade or sell the excess.
