The correct option is
C Wheat/Spinach
Short day plants require long period of darkness and short period of light to flower. Long day plants will flower when they are exposed to short period of darkness and long period of light. Long day plants flower in summer and short day plants flower in spring. Examples of short day plants are rice, tobacco, soyabean, xanthium. Examples of long day plants are lettuce, spinach, wheat, potato. So, the correct answer is 'Wheat/Spinach'