Final answer:
The family's greatest fear when the rice is three weeks away from harvest is drought destroying the crop.
Step-by-step explanation:
The greatest fear for the family when they still have three weeks to go before the rice is ready for harvest is d) Drought destroying the crop. Drought can prevent the rice plants from receiving enough water, which is essential for their growth. Without water, the plants may wither and die, resulting in a failed harvest.