The correct option is A Increase in trade between India and Europe.
South India and Sri Lanka seemed to be located in the north in Al-Idrisi's map drawn in 1154. However, the trade between India and Europe had increased a lot by 18th century. This led to a detailed idea of India's coastline, and the map drawn by a French cartographer in 1720 was much more accurate and detailed than that by Al-Idrisi.