Five Jobs Are Waiting for Processing Through Two Work Centres

Five jobs are waiting for processing through two work centres. Their processing time (in minutes) at each work centre is contained in the table below. Each job requires work centre Alpha before work centre Beta. According to Johnson's rule, what is the optimum sequence of jobs and the minimum time for completion of all jobs? $$\begin{array} { | c | c | c | } \hline \text { Job } & \text { Alpha } & \text { Beta } \\\hline R & 20 & 10 \\\hline \mathrm { S } & 25 & 35 \\\hline \mathrm { T } & 50 & 20 \\\hline \mathrm { U } & 15 & 35 \\\hline \mathrm { V } & 55 & 75 \\\hline\end{array}$$

A) V-T-S-U-R; 225
B) U-R-T-S-V; 175
C) R-S-T-U-V; 240
D) U-S-V-T-R; 200
E) V-U-T-S-R; 250