I need to find the risk free rate for a case I am doing. There are quotes provided for T-Bills T-Bonds. Which one should I use, the longest or

I need to find the risk free rate for a case I am doing. There are quotes provided for T-Bills & T-Bonds. Which one should I use, the longest or shortest maturity? And would the RF rate equal the coupon rate or yield of that bond/bill?

I need to find the risk free rate for a case I am doing. There are quotes provided for T­Bills & T­Bonds. Which one should I use, the longest or shortest maturity? And would the RF rate equal...