The three springs are positioned vertically, as illustrated. Springs P and Q are identical, and each has spring constant $k$. Spring R has spring constant $3k$. What is the rise in the total length of the arrangement when a force $W$ is applied as shown?
- A$\frac{5W}{6k}$
- B$\frac{4W}{3k}$
- C$\frac{7}{2}kW$
- D$4kW$