Let's analyze the problem step by step.
The letter which is four to the right of the letter C is G (C - D - E - F - G).
The letter immediately to the right of the letter G is H (G - H).
The letter which is four to the left of the letter H is D (H - G - F - E - D).
The letter two to the right of the letter D is F (D - E - F).
Therefore, the answer is F.