Answer:
The line that is an example of a subjective opinion is:
C. I believe that Frida's parents wanted to do everything to help her recover, including providing her with art materials.
Step-by-step explanation:
Lines A, B and D express facts, that is, events that have truly happened and that are most likely provable to be true. On the other hand, letter C expresses a subjective opinion. That means the author in this line is writing about what he/she believes happened. This is biased information based on the author's inferences, not a provable fact. We cannot take the author's word as 100% true. Opinions are often accompanied by expressions such as "I believe".