If = {a, b, c, d, e, f} then number of strings in of length 4 such that no symbol is used more than once in a string is

If = {a, b, c, d, e, f} then number of strings in of length 4 such

1.	If = {a, b, c, d, e, f} then number of strings in of length 4 such that no symbol is used more than once in a string is
A.	35
B.	360
C.	49
D.	720
Answer» C. 49