Pythagoras conducted his acoustical experiments after hearing and
intervals coming from a blacksmith shop.
A. consonant and dissonant
B. large and small
C. loud and soft
D. major and minor

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.