Need help in understanding the process of what to do for selling a put vs buying it in the following exercise:

EXERCISE #1: Options basics. Figure out the payoff and the profit per share in A-C: A. You sell a 47 put for 4. Stock ends at $48. Payoff: ................ Prot= ............................ B. You sell a 54 put for 4. Stock ends at $47. Payoff: ................. Profit= .......................... C. You sell a 50 put for 3, and buy a 45 put for 2. Stock ends at $45. Payoff: ................ Prot= ............................ D. You buy a 52 put when the stock trades at 49. Intrinsic Value= ............. Premium >