URGENTT PLEASEE!

200 kg of material with 40% humidity is dried at a constant drying rate (0.2 kg H2O/m2.h) until it is 20% moist, and then in a decreasing speed period (R=0.8 X) until it is 5% moist. Since the dryer area is 60 m2, what is the elapsed time in the decreasing speed period?

a) 6.06 hours

b) 8.07 hours

c) 4.17 hours

d) 3.9 hours