[单选题]
A spring with a spring constant of 15 N/m is initially compressed mr:m; r*z b5zty :frd2xxc 5;rby 3.0 cm. How much work is required to compcr5x2:fry d; xress the spring an additional 4.0 cm?
A. $0.0068 \; J$
B. $0.012 \; J$
C. $0.024 \; J$
D. $0.030 \; J$