Data Sufficiency

Could someone please explain the answer of this question. According to me, B is the right answer.
statement 1 alone is not sufficient. 15 boys in Biology gives only two numbers
total boys-Boys in biology=boys in NonBiology
18-15=3
and
total students in Biology-Boys in Biology =Girls in Biology
26-15=11

statement 2 provides a clue,
total girls in class =twice students not studying biology
so, lets assign a variable
total girls in class =x
students not studying biology=x/2
then
total boys+girls=Total students in Biology+Non Biology
26+x/2 = 18 +x
=> x=16

So statement 2 is sufficient to answer the question, total number of students in class=34

But the answer provided is C