Correct option is (b) Enhanced geothermal system
The explanation: The development of a geothermal system where hydraulic fracturing of the system can allow the production at a commercial level. EGS’s are engineered reservoirs created where there is geothermal energy but a lack of permeability. Fluid is injected into the earth‘s surface which causes pre-existing fractures to open again, creating permeability. Nationwide potential with engineered reservoirs 6-km to 8-km deep.