The correct answer is - c. the coast with Lake Victoria.
During the Scramble of Africa, the British had under their control large portions of the continent, and in order to strengthen their positions they started building railways. The railways were very useful for quicker transportation of people, soldiers, and goods, so the British invested in it so that they can get the maximum of the territory.
The building of the railway from the eastern coast to the Lake Victoria was a strategic move. This railroad enabled for easier transportation of goods, which contributed to the British to accumulate even more wealth. Also, it enabled an easier control of the African Great Lakes region, and being one step i front of the competition for the African territories.