According to me, she is sick or As I know, she is sick. (Sentence Correction)

According to me, she is sick.

As far as I know, she is sick.

"In my opinion, she is sick.

Both B&C

"As far as I know, she is sick" is correct and commonly used. It means that based on the information you have, you believe she is sick.

"In my opinion, she is sick" is also correct. It expresses your personal belief or judgment.

So, the correct and more natural options are:

B) As far as I know, she is sick.

C) In my opinion, she is sick.