The answer would be b, two violins, a viola, and a cello. the definition of a string quartet is a group of 4 musicians playing string instruments. all of the other answers would be wrong because they contain other instruments besides string instruments, like piano, horn, woodwind, and clarinet. i hope this helps! :D
Musical instruments of different types playing the same note may often be identified by the timbre of their sounds. Timbre is tone color, or tone quality which distinguishes different types of sound production.
