Answer
A, or gamma rays, is first in the list.
Work Step by Step
To figure out the answer to this, we must first analyze the question, which is asking us to list the types of electromagnetic radiation in order of increasing wavelength. Therefore, we can refer to Figure 6.4, on page 215.
This figure shows us that Gamma Rays have the lowest wavelength out of the five options. The question asks us to find the wavelengths in increasing order, meaning Option a is the first in the list, as it is the lowest.