Refer to the following series and answer the question (all numbers are single digit numbers only).
(Left) 6 4 5 7 8 4 6 3 1 4 1 2 7 4 9 1 5 3 6 1 1 (Right)
How many such odd digits are there each of which is immediately preceded by an even digit and also immediately followed by an odd digit?
AThree
BTwo
CFour
DOne