Fact 1: Biofuel is used to produce electricity by burning.

Fact 2: Wood and straw are both examples of biofuels.

Given the two facts above, answer the question "What is used to produce electricity by burning?" with the following options: 
- carbon
 - Oak
 - light
 - coal
 - fish
 - food
 - wood
 - oil


 

       wood  