Please answer d$.$ and e$.$

Problem $1.(40$ pts$)$ In Figure $1,$ the distillation configuration for separating benzene from toluene is given. The feed to the distillation comes from the reactor, where toluene has been hydrodealkylated to produce benzene:

toluene $+H_2$ benzene $+C{H}_4$

after the excess $H_2$ and the produced $C{H}_4$ have been removed in a flash unit. For the distillation system:

a$.(6$ pts$)$ Identify three potential control objectives $($consider profitable operation and safety$).$

b$.(6$ pts$)$ Identify three possible external disturbances.

c$.(8$ pts$)$ Identify four potential measurements and four manipulated variables.

d$.(10$ pts$)$ Suggest a feedforward controller that will control the operation of the column in the presence of changes in the feed flow rate.

e$.(10$ pts$)$ Suggest a feedback control configuration to account for changes in the feed flow rate.