The term Milankovitch cycles most closely relate to periodic changes in Earth’s orbit and angle of tilt relative to sun. So for this question, the correct option is option “c”. Milankovitch affects actually deals with the effect of the changes in the earth’s movements with the change in the climatic conditions. Milankovitch was a Serbian geophysicist and also a great astronomer. His studies actually helped in relating the climatic changes with the changes in the tilt of the earth. He was the first person to mathematically prove this situation.