Harsten’s theory was that plants definitely react to music

• Ordering of Sentences

S1: Harsten’s theory was that plants definitely react to music.
S6: He found that this plant grew faster and 70 percent taller than the other plant.

P: In his experiment, he used two banana plants.
Q: The music was in fact a high-pitched humming sound.
R: He gave both plants the same light, heat and water.
S: But for about an hour a day, one of the plants ‘listened’ to some music.

The proper sequence should be

1. Q S R P
2. P Q R S
3. P R S Q
4. Q R P S

Answer

The paragraph is about Harsten's theory and experiment conducted by him. "both plants" in sentence R refers to two banana plants mentioned in the sentence P. "But" in sentence S makes contraction to sentence R. The music mentioned in the sentence Q follows the sentence S.

The correct option is C.