Answer
Step-by-step explanation
A horizontal line of symmetry for each of the letter would include drawing a horizontal line across the middle of the letter and having the same exact shape above and below the line.
That doesn't work for
C
V
T
M
E
But it does work for
O
I
H
So, the group of letters given have only 3 letters with a horizontal line of symmetry.
Hope this Helps!!!