In the following list of letters, how many O's are followed by Q's but not preceded by D's ?
D O Q O D Q O D O D Q D O Q D S D Q P
O Q D S S S D O Q O Q D O Q D D D O Q
Answer: C
D O Q O D Q O D O D Q D O Q D S D Q P O
Q D S S S D O Q O Q D O Q D D D O Q