The contribution in the total current flowing through a semiconductor due to electrons and holes are \[\frac{3}{4}\] and \[\frac{1}{4}\] respectively. If the drift velocity of electrons is \[\frac{5}{2}\] times that of holes at this temperature, then the ratio of concentration of electrons and holes is

• A.            6 : 5                                          
• B.            5 : 6
• C.            3 : 2                                          
• D.            2 : 3