The correct answer is $\boxed{\text{B. Greater than Zero but less than One}}$.
Price elasticity of demand is a measure of how responsive consumers are to changes in the price of a good or service. It is calculated by dividing the percentage change in quantity demanded by the percentage change in price.
If the demand for rail travel is elastic, then a small change in price will lead to a large change in quantity demanded. This means that if the price of rail travel decreases, people will buy more rail travel, and if the price of rail travel increases, people will buy less rail travel.
If the demand for rail travel is inelastic, then a large change in price will lead to a small change in quantity demanded. This means that even if the price of rail travel decreases, people will not buy much more rail travel, and even if the price of rail travel increases, people will not buy much less rail travel.
If the demand for rail travel is unit elastic, then a change in price will lead to an equal change in quantity demanded. This means that if the price of rail travel decreases, people will buy exactly the same amount of rail travel, and if the price of rail travel increases, people will buy exactly the same amount of rail travel.
In the case where lowering of fares reduces railway’s revenues and increasing of fares increases, then the demand for rail travel has a price elasticity of demand that is greater than zero but less than one. This is because a change in price leads to a change in quantity demanded, but the change in quantity demanded is not equal to the change in price.