Answer:
Option: D. Hanif, who gives his neighbor Carla his freshly grown tomatoes in exchange for her expert lawn care.
Explanation:
Hanif is involved in bartering because he gives freshly grown tomatoes in exchange for her expert lawn care. A barter system is a medium of exchange where goods are changed, without any use of money. In ancient times, before coming of coins, bartering was much-practiced for exchange of goods.