What are the three types of solor ejections ?

Most ejections originate from active regions on the Sun's surface, such as sunspot groupings associated with frequent flares. Other forms of solar activity frequently associcated with coronal mass ejections are eruptive prominences, coronal dimming, coronal waves and Moreton waves, also called solar tsunami.

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint

looks like the answer is     c     to me!