3, 12, 7, 26, 15, ?
Choose the most appropriate option:
A) 34
B) 44
C) 54
D) 64
E) 74
3, ,7, ,15   (3*2)+1= 
<gadget id="calculator">(3*2)+1</gadget>
<output>7</output>
7   (7*2)+1= 
<gadget id="calculator">(7*2)+1</gadget>
<output>15</output>
15   12, ,26, ,?    (12*2)+2= 
<gadget id="calculator"> (12*2)+2</gadget>
<output>26</output>
26   (26*2)+2= 
<gadget id="calculator">(26*2)+2</gadget>
<output>54</output>
54   ANSWER:54
<result>C</result>
3, 12, 7, 26, 15, ?