$[10$ pt$]$ Suppose that the WFQ scheduling policy is applied to a buffer that supports three classes, and suppose the weights are $0\mathrm{.}5,0\mathrm{.}3,$ and $0\mathrm{.}2$ for the three classes. a$.$ Suppose that each class has a large number of packets in the buffer. In what sequence might the three classes be served in order to achieve the WFQ weights? $($For round$-$robin scheduling, a natural sequence is $123123123...).$ b$.$ Suppose that classes $1$ and $2$ have a large number of packets in the buffer, and there are no class $3$ packets in the buffer. In what sequence might the three classes be served to achieve the WFQ weights?