Correct option is A
The correct option is (a) SPRQ.
Explanation (Step-by-step arrangement):
- The opening fragment “Hybridization between” must be followed by a subject that completes the idea; S fits because it starts with “reproductively isolated species...” and forms a complete statement.
- S ends with “either”, and P begins with “parent.”, which perfectly completes the phrase “either parent.” Hence, P must follow S.
- P then introduces the contrast: hybrids are not always intermediate between their..., which must be completed by R (“parents but are sometimes stronger...”).
- Q logically comes last because it continues the idea and ends with “This is most common”, which is completed by the given ending “with plant hybrids.”
So the correct answer is (a)