A$.$ Suppose that:

Call premium $=$ $$3$

Spot price of asset $=$ $$20$

Time to maturity $=1$

r $=10\%$

Strike price K $=$ $$18$

The asset pays no dividend.

Write down the full arbitrage steps. What is the profit $$ amount $?$ B$.$ Suppose that

Call premium $=$ $$9$

Spot price of asset $=$ $$20$

Time to maturity $=1$

r $=10\%$

Strike price K $=$ $$18$

The asset pays no dividend.

Write down the full arbitrage steps. What is the profit $$ amount $?$ c$.$ Suppose that

Call premium $=$ $X

Spot price of asset $=$ $$20$

Time to maturity $=1$

r $=10\%$

Strike price K $=$ $$18$

The asset pays no dividend.

What value of the call premium X eliminates the arbitrage opportunity? Prove that your answer

is correct by writing down the full arbitrage steps and showing that profit $$ amount is in fact

$$0.$