How many strings of 6 letters can be made using only the letters A, B, and C, or only the letters D, E, and F ?  Pick
A) 2×3^6	B) 3×2^6	C) 3×3^6	D) 2×2^6	E) 6^6
3^6 + 3^6 = 2*3^6   2×3^6NS : 2×3^6
<result>A</result>
How many strings of 6 letters can be made using only the letters A, B, and C, or only the letters D, E, and F ?