28) C

1 – Correct
In order to make a fair comparison between the two types of buses, we need to know the distance that can be covered using one tonne of hydrogen and one tonne of traditional fuel. Using this data, we can then decide how much pollution will be produced by each type of bus.

2 – Wrong
We do not really need to know the distance covered by each bus on a weekly basis. Also, the new buses travel on the same routes as the old ones. So they will be covering roughly the same distance as the traditional buses.

3 – Correct
We also need to know the amount of carbon dioxide produced by one tonne of traditional fuel. Then we can compare this with amount of carbon dioxide emitted by hydrogen and make a informed decision about which fuel is better.

4 – Correct
The text does say that transportation of fuel to the depot also needs to be considered. To make a fair comparison, we need to know how much carbon dioxide is emitted when each type of fuel is transported.

Statements 1, 3 and 4 are correct. So, C is the answer.