Refer to the given number series and answer the question that follows. Counting to be done from left to right only.
(Left) 4 3 5 6 2 1 5 5 7 1 5 2 3 6 9 7 4 7 9 5 8 5 3 7 4 2 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 even digit?
A2
B1
C3
D4