Part (a)

Let's denote current stock price as S_{0, }call premium as C, put premium as P, strike price as K, present value of K as PV (K), risk free rate as r and time to expiration as t then,

Call Put Parity Equation:

C + PV (K) = S_{0} + P

Or, C + K x (1 + r)^{-t} = S_{0} + P

Hence, K x (1 + r)^{-t} = S_{0} + P - C

Hence, a synthetic Treasury bill position is:

- Buy (long) a stock
- Buy (long) a put option
- Short a call optionj