“The crop is subtropical in nature. A hard frost is injurious to it. It requires at least 210 frost-free days and 50 to 100 centimeters of rainfall for its growth. A light well-drained soil capable of retaining moisture is ideally suited for the cultivation of the crop.” Which one of the following is that crop?

The correct option is Cotton.

Let us break down the agricultural requirements mentioned in the question to understand why Cotton is the correct crop:
1. Climate: Cotton is a subtropical crop that requires a warm climate. A hard frost is highly injurious to the crop, especially during its growing period.
2. Frost-free days: A critical and distinguishing requirement for cotton cultivation is a long, warm growing season. It requires at least 210 frost-free days to mature fully.
3. Rainfall: Cotton grows well in areas receiving moderate rainfall ranging between 50 and 100 centimeters. High rainfall or waterlogging is harmful to it.
4. Soil: It thrives best in deep, well-drained soils that can retain moisture. The black cotton soil (regur soil) of the Deccan Plateau in India is particularly ideal because of its high clay content and moisture-retentive capacity, though it also grows well in light, well-drained alluvial soils.

Comparing these conditions with the other options:
- Jute requires a hot and damp climate with high rainfall (usually above 150 cm) and is not characterized by the 210 frost-free days requirement.
- Sugarcane is a tropical as well as subtropical crop but requires higher rainfall (around 75 to 100 cm or more) and a long frost-free period, but it does not have the specific "210 frost-free days" benchmark typically associated with cotton's growth cycle.
- Tea requires high rainfall (150 to 250 cm) distributed throughout the year and deep, fertile, well-drained acidic soils, which differs significantly from the moderate 50-100 cm rainfall requirement of cotton.

Thus, all the given conditions perfectly describe the cotton crop.