Answer:
d) decease in demand
Step-by-step explanation:
When the produce of sweet corn crop rises by 20%, this would lead to an increase in supply. With increase in supply, the price of sweet corn shall fall, which would lead to an increase in demand as now consumers will consume more of sweet corn.
Since the relationship between price of a good and demand for it's substitute is positive, the demand for the substitute shall fall.
Thus, demand for frozen peas shall decrease as demand for sweet corn has increased.