Look at this series: 3, 4, 7, 8, 11, 12, ... What number should come next? Choose one:	A) 11	B) 14	C) 15	D) 17	E) 19
15   15   This alternating addition series begins with 3; then 1 is added to give 4; then 3 is added to give 7; then 1 is added, and so on.
<result>C</result>
Look at this series: 3, 4, 7, 8, 11, 12, ... What number should come next?