A puppy weighs 2.8 pounds at birth and gains about .5 pounds per week. A kitten weighs 1.4 pounds at birth and gains about 1.2 pounds per week. In how many weeks will the weight of the kitten be less than the weight of the puppy?

a. 1.4 + 1.2x 2.8 + .5x
c. 1.4x + 1.2 2.8x + .5