Name Count String Fret

The frets on the guitar are the metal strips placed along the fretboard. The first fret is the metal strip closest to the headstock of the guitar, and then it counts up from there.

Most people think the string closest to them, the thickest string, is the first string of the guitar, but it’s actually the opposite. The string closest to the floor, the thinnest string, is the first string. The next string up, the second thinnest string, is the second string, and so on from there. Just be aware that your thinnest string is the first string, and the thickest string is the sixth string.

Explanation:

they are often in theme and variations

i would think b and c