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What is the correct answer?


Pick up the correct statement from the following:

A. Refraction correction is zero when the celestial body is in the zenith

B. Refraction correction is 33' when the celestial body is on the horizon

C. Refraction correction of celestial bodies depends upon their altitudes

D. All the above

Please do not use chat terms. Example: avoid using "grt" instead of "great".