$(21$ pts$)$ In each of the following problems, is each microinstruction possible for the simple computer to execute in one single clock cycle $($i$.$e$.,$ one step$)?$ If not, replace it with a new microinstruction or a sequence of microinstructions that perform the same intended function. You only need to write the register transfers, no need to write any control lines or states. $(3$ pts each$)$

a$.[MAR]+[AC]x$

b$.[MDR]+[PC]IR$

c$.$

$[IR]x$

$[x]+[AC]AC$

d$.\left[\begin{array}{c}\text{M}\text{A}\text{R}\end{array}\right]$ MAR

e$.[MAR]MDR$

f$.[MDR][MAR]$

g$.\left[\begin{array}{c}MDR\end{array}\right]$MAR