Traditional instruments often used in Tamil folk music include:

Thavil and Nadaswaram
Veena and Mridangam
Sitar and Tabla
Harmonium and Keyboard

The correct answer is: a) Thavil and Nadaswaram.

Thavil is a large double-headed drum that is played with sticks. It is used in religious ceremonies and temple festivals. Nadaswaram is a wind instrument that is made of wood and brass. It is played with a mouthpiece and produces a loud, piercing sound.

Veena is a stringed instrument that is played with the fingers. It is made of wood and has seven strings. Mridangam is a double-headed drum that is played with the hands. It is made of wood and has a deep, resonant sound.

Sitar is a stringed instrument that is played with a plectrum. It is made of wood and has seven strings. Tabla is a pair of drums that are played with the hands. They are made of wood and have a high-pitched sound.

Harmonium is a keyboard instrument that is played by pressing down on keys. It produces a sound that is similar to an organ. Keyboard is a musical instrument that is played by pressing down on keys. It can produce a variety of sounds, including those of other instruments.

Thavil and Nadaswaram are the most common instruments used in Tamil folk music. They are used in a variety of genres, including religious music, dance music, and folk songs.