Humidity = β0 + β1Temperature + β2Spring + β3Summer + β4Fall + β5Rain + ε, where the dummy variables Spring, Summer, and Fall represent the qualitative variable Season (spring, summer, fall, winter), and the dummy variable Rain is defined as Rain = 1 if rainy day, Rain = 0 otherwise. Assuming the same temperature and precipitation condition, what is the difference between the predicted humidity for summer and winter days?
a. b0 + b1 + b5b. b0 + b3 + b5
c. b3