47. Assume that short-term investment securities are yielding 5 percent, and it costs a firm $20 each time it buys or sells investment securities. The variance of the firm's daily net cash flows has been found to be $20,000. Management wants to keep at least $1,000 in the cash account for emergencies. Given these conditions, what is the firm's target cash balance? a. $3,289 b. $2,299 C. $3,450 d. $2,348