Will an at-the-money call finish in the money?

A stock trades at 100 with volatility $\sigma = 20\%$ and the risk-free rate is $r = 0$. Consider an at-the-money call ($K = 100$). (a) What is the risk-neutral probability that it finishes in the money for $T = 1$ and for $T = 4$? (b) Is it above or below one half, and why? (c) If the stock's real drift is $\mu = 10\%$, what is the real-world probability for $T = 1$, and does it affect the price?