The mercantile system motivated European countries to explore new lands hoping to do what

The correct answer is - accumulate bigger wealth.

The mercantile system is an economic system, which in its essence has it that a nation should be increasing its trade in order to make bigger wealth, and that should be done by using protectionism.

The European powerhouses were trying to implement this way of economic theory, so they were conquering new territories in order to get more materials and goods, exploit the local populations as cheap labor force, develop their industry and manufacture more and more, and also open up new markets in order to sell the final products.

The mercantile system motivated European countries to explore new lands hoping to find a sea route to Asia. The Silk Road was the only way to trade goods with Asia. Traveling down that road has become dangerous because the Ottoman empire was powerful.