A sequence of numbers starts with 1,2 and 3 . The fourth number of the sequence is the sum of the previous three numbers in the sequence: 1+2+3=6. In the same way, every number after the fourth is the sum of the previous three numbers. What is the eighth number in the sequence?
Answer Choices
A. 11
B. 20
C. 37
D. 68
E. 99