The first step in implementing the Clarke$-$Wright Method is to compute the savings for all pairs of customers. A local

restaurant franchise has four locations in one city. Each week, cases of taco shells must be delivered from the central

warehouse to the restaurants. The table below shows the travel time in minutes between the locations $(1,2,3,4),$ as well as to

and from the warehouse $($o$).$

Which pair of customers $s(i,j)$ has the largest savings?

a$.1,2$

b$.1,3$

c$.2,3$

d$.2,4$