Read the paragraph below and choose the best option indicating what They refers to.
Fossil fuels are the remains of dead plants and animals over several millions of years. Those remains became energy resources like coal, fuel oil o They are easily processed and transportation is mostly done through pipes. Many people would prefer the easily combustible and cheap resources Since even their extraction and processing is often very cheap. Many countries use inexperienced or uninstructed labour, and do not invest in materials for the workers, which leads to many work accidents or explosions, and even several deaths among workers.
1) Dead plants and anımals
2) Fossil fuels
3)Plats and anımals
4) the remains