7614. They are cautiously optimistic about the effects of the new medicine.

✅ The correct answer is option A.
Carefully : in a way that deliberately avoids harm or errors; cautiously.

Genuinely : in a truthful way.

Secretly : in a secret way; without others knowing.

Curiously : in a way that shows eagerness to know or learn something.

Cautiously : in a way that deliberately avoids potential problems or dangers.

Synonym of Cautiously is Carefully