The correct option is A Mumbai
According to Mercer’s 24th annual Cost of Living Survey 2018, Mumbai (55) is India’s most expensive city, followed by New Delhi (103) and Chennai (144). Kolkata (182) and Bengaluru (170) are the least expensive Indian cities ranked. As per survey, the factors like instability of housing markets, low inflation, and fluctuating prices for goods and services are impacting the cost of doing business in various cities around the world. This year, Hong Kong is emerged as the most expensive city for expatriates both in Asia and globally as a consequence of Luanda’s drop in the ranking due in part to the downward trend in the city’s housing market. Hong Kong is followed by Tokyo (2), Singapore (4), Seoul (5), Shanghai (7), and Beijing (9).