The amihan season brings the best weather condition in the Philippines. The air is cool, there is less rain and the humidity is low. If the temperature is 20⁰C, drops 4⁰C , rises 9⁰C and then drops by 3⁰C by 4 p.m. , what is the temperature by 4 p.m.?

a. 37⁰C
b. 22⁰C
c. 12⁰C