Look at this series: 15, __, 27, 27, 39, 39, ... What number should fill the blank? Choices:  A) 10  B) 16  C) 18  D) 11  E) 15
15   11   In this simple addition with repetition series, each number in the series repeats itself, and then increases by 12 to arrive at the next number.
<result>E</result>
Look at this series: 15, __, 27, 27, 39, 39, ... What number should fill the blank?