You can trade two assets in Market #$1$ at a rate of $4A=1B$ and in Market #$2$ at a rate of $\mathrm{.}3B=1A.$ In either market, you have the option of selling A to buy B or of selling B to buy A$.$ Assume there are no transaction costs and you can make multiple trades simultaneously. You should:

a$.$ Do nothing; there is no arbitrage opportunity here.

b$.$ Sell A to buy B in Market #$1$ and then immediately sell A to buy B in Market #$2.$

c$.$ Sell B to buy $A$ in Market #$1$ and then immediately sell B to buy A in Market #$2.$

d$.$ Sell $A$ to buy B in Market #$1$ and then immediately sell B to buy A in Market #$2.$

e$.$ Sell B to buy A in Market #$1$ and then immediately sell A to buy B in Market #$2.$