1. The problem asks to find at least four capital letters from the English alphabet that have rotational symmetry of order 2. 2. Rotational symmetry of order 2 means the letter looks exactly the same when rotated 180 degrees (turned upside down). 3. We examine each letter: A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z. 4. Letters with rotational symmetry of order 2 are those that appear unchanged after a 180-degree rotation. 5. Checking each letter: - H looks the same upside down. - I looks the same upside down. - N looks the same upside down. - O looks the same upside down. - S looks the same upside down. - X looks the same upside down. - Z looks the same upside down. 6. Therefore, at least four letters with rotational symmetry of order 2 are: H, I, N, O. 7. Final answer: H, I, N, O