这两个公式怎么来的呢？

问题如下：

Consider a stock that pays no dividends, has a vol. of 30% per annum, and provide an expected return of 15% per annum with continuous compounding. The stock price movements follow GBM. Consider a time interval of 1 week and the initial stock price is 100, then the stock price increase has a normal distribution with:

选项：

A.

Mean = 0.268%, standard deviation = 4.03%

B.

Mean = 0.278%, standard deviation = 4.13%

C.

Mean = 0.288%, standard deviation = 4.16%

D.

Mean = 0.288%, standard deviation = 4.27%

解释：