Based on the number of plane accidents in the recent past, someone makes the statement that air travel is riskier than train travel. In order to make his statement fully correct, he must
1
have the number of plane accidents that happened for the past several years.
2
have the data about the number of flights and train operated over a reasonable period of time, along with the number of accidents of both these modes of transport.
3
have the number of plane accidents and train accidents over the last several years.
4
number of flights operated and the number of plane accidents for last several years.