"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?

Let's break down the characteristics described and match them to the given crops: "The crop is subtropical in nature." Cotton thrives in tropical and subtropical climates. "A hard frost is injurious to it. It requires at least 210 frost-free days..." This is a very specific and critical requirement for cotton. Cotton plants are highly sensitive to frost; a single frost event can severely damage or destroy the crop. A minimum of 200-210 frost-free days is essential for its successful growth and maturity, ensuring a long, warm growing season. "...and 50 to 100 centimeters of rainfall for its growth." Cotton needs moderate rainfall, well-distributed throughout its growing period, but not excessive. This range is suitable. "A light well-drained soil capable of retaining moisture is ideally suited for the cultivation of the crop." Cotton grows best in deep, fertile, well-drained soils. Black cotton soil (Regur soil), known for its moisture-retaining capacity, is particularly ideal for cotton cultivation due to its clayey nature and ability to swell and shrink, which helps in self-aeration. Comparing these requirements with the options: A) Cotton: Perfectly matches all the given characteristics, especially the high requirement for frost-free days and preference for moisture-retaining, well-drained soil. B) Jute: Requires high temperatures and high humidity, with much higher rainfall (150-250 cm), and usually grows in alluvial plains. While it's a tropical crop, the specific frost-free days and rainfall range do not fit as precisely as cotton. C) Sugarcane: Subtropical to tropical, sensitive to frost, requires significant rainfall (100-150 cm) or irrigation, and deep rich loamy soil. While some aspects match, the combination of all factors, particularly the precise frost-free days, points more strongly to cotton. D) Tea: Prefers tropical and subtropical highland regions, well-distributed heavy rainfall (150-300 cm), and well-drained acidic loamy soils. Frost can be damaging, but the other specific conditions, especially rainfall, do not align as well. Thus, the description accurately points to Cotton.