Answer:
The correct answer is - a. an earlier start to spring
Step-by-step explanation:
A longer growing or flowering season of a plant is a result of an earlier start to spring as it will start earlier than usual due to the warmer conditions in the environment.
Due to this longer growing and flowering season, the growth of the plant will also be increased as result. If the temperature is high and conditions are warmer that might start early spring.
Thus, the correct answer is - a. an earlier start to spring