Look at this series: V, VIII, __, XIV, XVII, XX, ... What number should fill the blank?
Choose the correct answer:  A) IX  B) XXIII  C) XV  D) XI  E) None
Explanation: This is a simple addition series; each number is 3 more than the previous number.   Answer: XI
<result>D</result>
Look at this series: V, VIII, __, XIV, XVII, XX, ... What number should fill the blank?