This is not an obvious inference, but lines 13-19 tell us that "renewable energy sources are available in virtually all geographic regions" and "they can be located closer to customers, thereby reducing transmission and distribution costs." The question asks us which of the following the author most likely to agree with, and (A) accurately represents the author's overall perception of the solar potential. Despite difficulties - Brazil example in paragraph 2 - he believes that solar provides a possible solution, is available worldwide, and at lower cost than conventional sources.
(C) is unsupported by the passage, it is true that air quality issues will be more prevalent in urban areas, but nothing suggests that solar installations could be deployed more effectively in urban rather than rural areas. (E) contradicts the information in this passage, lines 10-11 tell us that solar systems present a possible solution to the increasing electricity demand, the author never says they are not viable just because solar panels were too costly to produce in Brazil.