Over the last 10 years four mutual funds all had the same mean rate of​ return, 12%. These mutual funds had different standard deviations. The standard deviations for Mutual Fund A​ 8%, Mutual Fund B​ 6%, Mutual Fund C​ 4%, Mutual Fund D​ 9%. Which mutual fund investment is the most consistent in rate of​ return?
(A) Together Fund
(B) All for One Fund
(C) Co-joined Investments
(D) Mutual Money