Consider two securities that pay risk$-$free cash flows over the next two years and that have the current market prices shown here: Data table

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a$.$ What is the no$-$arbitrage price of a security that pays cash flows of $$500$ in one year and $$500$ in two years?

b$.$ What is the no$-$arbitrage price of a security that pays cash flows of $$500$ in one year and $$4,500$ in two years?

c$.$ Suppose a security with cash flows of $$250$ in one year and $$500$ in two years is trading for a price of $$650.$ What arbitrage opportunity is available?

a$.$ What is the no$-$arbitrage price of a security that pays cash flows of $$500$ in one year and $$500$ in two years?

The no$-$arbitrage price is $$.($Round to the nearest dollar.$)$