Which sequence shows the different types of electromagnetic waves arranged in an increasing order of their frequency?
There is no sequence on your list that shows anything like that.
If you find a sequence that purports to do it, check and see that it
has radio first and gamma rays last. That sequence is a good bet,
although there can't be any guarantee until you all check all the others
in the middle.
Select one:
a. Wave 1, Wave 4, Wave 3, Wave 2
b. Wave 2, Wave 1, Wave 3, Wave 4
c. Wave 3, Wave 4, Wave 1, Wave 2
d. Wave 4, Wave 3, Wave 1, Wave 2
D is the correct answer!