He harvested a rich crop from that fecund land.

Answer: Option C

Fecund : producing or capable of producing an abundance of offspring or new growth; highly fertile.
Fertile : (of soil or land) producing or capable of producing abundant vegetation or crops.
Obsolete : no longer produced or used; out of date.
Barren : (of land) too poor to produce much or any vegetation.
Fruitless : failing to achieve the desired results; unproductive or useless.

Antonym of Fecund is Barren