The correct answer is Option 4: A is false but R is true.

Assertion (A): Urbanisation has been invariably a result of industrialisation. — Incorrect. Urbanisation is often associated with industrialisation, but it is not always the result of industrial growth alone. Cities can also develop due to administrative, political, commercial or historical reasons. The use of the word “invariably” makes the statement incorrect.

Reason (R): Industrial centres attracted workers and encouraged the concentration of population in towns and cities. — Correct. The growth of industries created employment opportunities, attracting workers and leading to the expansion of urban centres.

NCERT: While it's true that urbanisation and industrialisation often appear together historically, not every instance of urbanisation directly arises from industrialisation. Other factors like technological advancements, changing economic structures, and migration patterns can also contribute to urban growth. Therefore, saying they "occur together" isn't an entirely accurate explanation for the association between urbanisation and industrialisation.

Industrialisation refers to the emergence of machine production, based on the use of inanimate power resources like steam or electricity. In most standard western textbook of sociology we learn that in even the most advanced of traditional civilizations, most people were engaged in working on the land. The relatively low level of technological development did not permit more than a small minority to be freed from the chores of agricultural production. By contrast, a prime feature of industrial societies today is that a large majority of the employed population work in factories, offices or shops rather than agriculture. Over 90 per cent of people in the west live in towns and cities, where most jobs are to be found and new job opportunities are created. Not surprisingly, therefore, we usually associate urbanisation with industrialisation. They often do occur together but not always so.