In the double application of principle of reversion, the apparent error is A. equal to true error B. half the true error C. two times the true error D. four times the true error

The correct answer is: C. two times the true error.

The principle of reversion states that the apparent error is equal to the true error multiplied by the number of times the principle is applied. In the double application of the principle of reversion, the apparent error is equal to the true error multiplied by 2.

Option A is incorrect because the apparent error is not equal to the true error. Option B is incorrect because the apparent error is not half the true error. Option D is incorrect because the apparent error is not four times the true error.