How many such sevens are there in the given series each of which is immediately preceded by 9 and also immediately followed by 8?
6 7 8 9 9 8 7 9 7 7 8 9 7 8 7 6 9 6 8 9 7 7 9 8 9 7 6 8 8 7
ANone
BOne
CTwo
DThree
there is only one
there is only one