Which line is example of a subjective opinion?

During the summer of 1932, Frida Kahlo experienced a relapse and was forced to stay in bed.
Guillermo Kahlo experienced great stress over his daughter’s health and mounting medical bills.
I believe that Frida’s parents wanted to do everything to help her recover, including providing her with art materials.
Family and friends were the first subjects that Kahlo painted during her recovery.