A builder needs to lay a concrete path around the outside of an 18 m by 15 m rectangular area of grass. If the width of the path must be 1 m and the concrete must have a depth of 10 cm , then the amount of concrete that the builder needs, correct to one decimal place, is
Select one:
a. \( 74,0 \mathrm{~m}^{3} \).
b. \( 70,0 \mathrm{~m}^{3} \).
c. \( 7,0 \mathrm{~m}^{3} \).
d. \( 7,4 \mathrm{~m}^{3} \).