For an ungrouped data of 10 scores Arithmetic mean is 12. If one more socre is joined to the previous scores the mean increases by 0.5 with this information.

Ravi: Ravi says that the new score will be 0.5 more than 12.

Harsha : Harsha says that the new score will be 5.5 more than 12.

Ritu : Ritu says that sum of 11 scores is 17.5 greater than sum of 10 scores. Now, which of these is correct?

A) All are correct.

B) Ravi and Harsha are correct.

C) Harsha and Ritu are correct.

D) Ravi and Ritu are correct.