Four of the wavelengths of the Balmer series occur in the visible spectrum (656 nm, 486 nm, 434 nm, and 410 nm). In which region of the electromagnetic spectrum does the fifth line, with a wavelength of 397 nm, occur?

a) X rays
b) gamma rays
c) radio waves
d) ultraviolet
e) visible light
f) infrared
g) microwaves