Statement 1: The refractive index of the ionosphere increases as we go from the lower to upper layers in the ionosphere.
Statement 2: The degree of ionization is higher at the upper layers then at the lower layers of the ionosphere.
A. Both statement-1 and statement-2 are true, and statement-2 is the correct explanation of statement 1.
B. Both statement-1 and statement-2 are true but statement-2 is not the correct explanation of statement-2
C. Statement-1 is true but statement-2 is false.
D. Statement-1 is false but statement-2 true.