So what is the purpose of solar power pump - to lower the underground water. 'to verb' shows purpose of verb of the sentence.
what firm has proposed - two things and these two should be parallel - 1. installing pumps, 2. digging trenches
only C is following these two needs.
what firm has proposed - two things and these two should be parallel - 1. installing pumps, 2. digging trenches
only C is following these two needs.
