Identify which statement is an expression of a mere opinion.
a. The weekly update about the number of COVID - 19 positive cases was confirmed by the Department of Health. b. According to the result of the tests, there were only five people who came to be infected.
c. Scientists confirmed that the only cure to the deadly virus is to come up with a vaccine.
d. Other doctors suspect that the spread of the virus started not from the bats but from a laboratory.​