Option (a) is correct.

Assertion A is correct because the passage states that landlocked countries were at a developmental disadvantage, which was probably greater in an earlier era when transportation and communication costs were much higher. Therefore, Reason R also correctly explains why the developmental disadvantage of landlocked countries was greater in earlier times.

विकल्प (a) सही है ।

अभिकथन A सही है क्योंकि गद्यांश में कहा गया है कि स्थलरूद्ध देश विकासात्मक नुकसान में थे, जो शायद पूर्ववर्ती काम में अधिक था जब परिवहन और संचार लागत बहुत अधिक थी। इसलिए, कारण (R) यह भी बताता है कि स्थलबद्ध देशों का विकासात्मक नुकसान अधिक क्यों था।