Assertion (A): The distance between India and the Western countries was shortened by the construction of the Suez Canal.
In Assertion-Reason, check both parts calmly. Here, the combination that fits is Both (A) and (R) are true and (R).... In Canals, this is how Assertion and Reason are linked. If you check Assertion first, then Reason, then the link, the answer becomes clear. That is the simple way to do it.
Ref: [UPPCS (Pre) 1992] | NCERT Geography textbooks and Goh Cheng Leong, Certificate Physical and Human Geography, discuss Canals and explain the geographical concepts and processes that support the correct answer for this question.