Mr. chambliss is planning to build a shed with a rectangular floor. in his original plan, the length of the floor was 7 feet and the area of the floor was 35 square feet. in his new plan he wants to extend the length by 3 more feet. if the total area of the shed will be 70 square feet, by how many feet will he have to extend the width?

a. 1 foot
b. 2 feet
c. 3 feet
d. 4 feet