The correct answer is option D (supertonic, mediant, and submediant)
In a major key, the supertonic and mediant triads (ii and iii) are minor, and the submediant triad (vi) is also minor. <span>The diatonic triads in the key of C major are typically identified with roman numerals as expressed in the brackets.</span>
This was applied to an excellent achromatic telescope of 34 in.
///// the answer is D /////
