Fact 1: Riding a bike does not cause pollution.

Fact 2: Bikes are good for exercise and produce no pollution.

Given the two facts above, answer the question "What can you ride to get good exercise and avoid producing harmful gases?" with the following options: 
- cows
 - bike
 - stairmaster
 - cycles
 - bus
 - trolley
 - Lift
 - goats


 

  bike       