Final answer:
In Henry Purcell's opera 'Dido and Aeneas,' the basso continuo is played by the harpsichord and cello, which provide harmonic support and improvise accompaniment.
Step-by-step explanation:
The instruments that play the basso continuo in Henry Purcell's opera Dido and Aeneas are the harpsichord and cello. Option c is correct. Basso continuo is a form of musical accompaniment used in the Baroque period that typically includes a keyboard instrument such as the harpsichord, organ, or harpsichord, along with a low stringed instrument like the cello or bass viol. These instruments provide the harmonic framework for the piece and often improvise chordal accompaniment over a written bass line, a practice known as 'realizing' the figured bass.