It is so gratifying to know that there are not many small-pox cases these days.

A. pleasing

B. surprising

C. satisfying

D. happy

Answer: Option C

Solution(By Examveda Team)

Displease : make (someone) feel annoyed or upset.
Surprising : causing surprise; unexpected.
Satisfying : giving fulfilment or the pleasure associated with this.
Happy : feeling or showing pleasure or contentment.
Gratifying : giving pleasure or satisfaction.

Synonym of Gratifying is Satisfying