A secondary source is:

Select the best answer choice.
A.
Stealing other people's ideas
B.
Sources created at the time of the historical event
C.
Developed by researchers using primary sources
D.
Sources that were written by people who were involved in that event

C, Developed by researchers using primary sources.

Explanation:

Secondary sources were created by someone who did not experience first-hand or participate in the events or conditions you're researching.

steps:

1. do 28-12= 16 girls

2. your ratio is 12: 16

3. your answer is b. 3/4

4. this correct because

12 divided by 4 is 3

16 divided by 4 is 4

5. your answer is 3/4

the simple predicate of the sentence is camped.