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 .47 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 $3,450 .a O $2,299.b O $3,289.co $2,348 .d O