D, because there are several students that are in your school. There would be many different answers.
To find this, first find the factor or rate of which the numbers are moving. To do so do as follows.
subtract 1 from 3
3-1=2
So each number is having 2 added to it.
Now add two to 7 and the numbers afterwards till you get the 12th term
7+2=9
1+3+5+7+9
9+2=11
1+3+5+7+9+11
11+2=13
1+3+5+7+9+11+13
13+2=15
1+3+5+7+9+11+13+15
15+2=17
1+3+5+7+9+11+13+15+17
17+2=19
1+3+5+7+9+11+13+15+17+19
19+2=21
1+3+5+7+9+11+13+15+17+19+21
21+2=23
1+3+5+7+9+11+13+15+17+19+21+23
So 23 is the 12th term
Here is your perfect answer