Can someone interpret this line for me?

(this is in a class)
def in_fahrenheit
@options.key?(:f) ? @options[:f] : (@options[:c] * 9.0 / 5) + 32

The 2nd line. I understand the first part of the line is returns a
Boolean depending on if there exists a key “:f.” Then what does the rest
of it mean?

I was able to find the answer for myself!

This link was useful: