What is the triad built on the 4th scale degree of the C major scale?

The triad built on the 4th scale degree of the C major scale is indeed F major, which consists of the notes F, A, and C. In the context of the C major scale, the scale degrees are as follows:

1st - C

2nd - D

3rd - E

4th - F

5th - G

6th - A

7th - B

The fourth degree is F, and when a triad is formed, we take the 1st, 3rd, and 5th notes of the scale starting from F. This gives us F (the root), A (the third), and C (the fifth), which together form the F major triad.

It's important to recognize that other options provided consist of triads originating from different scale degrees. For example, the G major chord comes from the 5th degree, while the C major triad is based on the root of the scale. E minor is rooted on the 6th scale degree, adding further distinction to the choice of F major as the correct answer. Thus, F major is definitively linked to the 4th scale degree of the C major scale, making it the right choice.