How many combinations of three letters taken from letters (a, a, b, c, c, d) are possible?	Select the correct option:
A) 12	B) 13	C) 10	D) 36	E) 56
So 4103 for abcd - 4 choices   3 more for aa(b,c or d)   3 more for cc(a,b or d)   total 10   Ans :10
<result>C</result>
How many combinations of three letters taken from letters (a, a, b, c, c, d) are possible?