Originally Posted by: equatorIt is not what I choose to label it. It is what Music Theory calls it.
A "G major pentatonic scale" is gonna show an "F#" in the key signature in standard notation, because the parent scale is G Major not "C Major"
In the same way a "D minor pentatonic scale" is gonna show a "Bb" in the key signature, because the parent scale is D minor; not "C major".
So, if you play those scales you can`t say that you are playing a C major scale. You would be playing a G major pentatonic scale over "C" in the first case and, a D minor pentatonic over "C" in the second case.

And yes. You would say D dorian when you play the second mode of the C major scale, or C dorian when you play the second mode of the "Bb major scale".
You can read more about this in:
Guitar World
presents
Jhon Petrucci`s
Wild Stringdom.

We're talking about a song in Cmajor aren't we? Why do songs in different keys concern us? Yes, if the song were in G major there would be an F# in the key signature. I'm saying no matter what you choose to label the scale you're playing over the C major backing (if it is a relative scale you indeed are playing, which is what you indicated in the post I responded to), in actuality you are playing the same notes as are in the C major scale, emphasizing root and fifth, and thus playing a Cmajor scale. Even if you call the notes you're playing "D Dorian" or "G Mixolydian," if your root is still C, you're playing C major. Until your root changes to D or G you're not actually playing these relative scales.
You can read more about this in the introductory chapters of either:
Structural Functions in Music
by Wallace Berry

or

Harmony and Voice Leading 3rd Edition
Ed. Edward Aldwell & Carl Schachter