Five Jobs Are Waiting for Processing Through Two Work Centers

Multiple Choice

Five jobs are waiting for processing through two work centers. Their processing time (in minutes) at each work center is contained in the table below. Each job requires work center Sigma before work center Delta. According to Johnson's rule, what sequence of jobs will minimize the completion time for all jobs?
$$\begin{array} { | c | c | c | } \hline \text { Job } & \text { Sigma } & \text { Delta } \\\hline R & 40 & 10 \\\hline \mathrm { S } & 25 & 30 \\\hline \mathrm { T } & 50 & 20 \\\hline \mathrm { U } & 35 & 35 \\\hline \mathrm { V } & 55 & 15 \\\hline\end{array}$$

A) R-S-T-U-V
B) S-V-T-R-U
C) S-U-T-V-R
D) V-R-U-S-T
E) none of the above