The most relevant reason among the options provided for why Europeans wanted to find a maritime route to the East is:
They were hoping to beat the Ottomans in establishing trading posts in the Indian Ocean.
This choice highlights the competitive nature of European powers during the age of exploration, as they sought new trade routes and access to valuable goods, such as spices, silks, and other commodities that were controlled by the Ottomans and other intermediaries on the traditional land routes. The desire to establish direct trade routes to bypass these intermediaries was a major driving factor behind maritime exploration.