The acoustic guitar ... any standard tuned version. Secondly, the maj7th (B) ringing adjacent to the open C (root) on the second string gives an interesting dissonance. A movable chord using ...
All fairly standard ... Root (C) - dominant 7th (Bb) - 9th (D) - 11th (F). Again, the 5th is omitted, which helps with fingering on the guitar, but it’s also common practice to stop chords ...