<u>Given</u>:
Given that the graph OACE.
The coordinates of the vertices OACE are O(0,0), A(2m, 2n), C(2p, 2r) and E(2t, 0)
We need to determine the midpoint of EC.
<u>Midpoint of EC:</u>
The midpoint of EC can be determined using the formula,

Substituting the coordinates E(2t,0) and C(2p, 2r), we get;

Simplifying, we get;

Dividing, we get;

Thus, the midpoint of EC is (t + p, r)
Hence, Option A is the correct answer.