Fact 1: Tidal energy can be used to produce electricity.

Fact 2: Ocean thermal is energy derived from waves and also from tidal waves.

Given the two facts above, answer the question "what can be used to produce electricity?" with the following options: 
- ocean thermal
 - a hydraulic system
 - a delta
 - Firecrackers
 - by indirect light
 - engines
 - hydrogen and oxygen
 - rays or beams


 

 ocean thermal        