We came in peace for all mankind what does this signify

On July 20, 1969, two American astronauts made history by landing on the surface of another celestial body.

This image is a close-up view of the plaque, which Apollo 11 Commander Neil Armstrong and lunar module pilot Buzz Aldrin left on the Moon in commemoration of the historic lunar landing mission. The plaque was attached to the ladder on the landing gear strut on the descent stage of the Apollo 11 lunar module. The plaque was covered with a thin sheet of stainless steel during flight. Astronaut Michael Collins, command module pilot, remained with the command and service modules in lunar orbit while Armstrong and Aldrin explored the Moon.

Image Credit: NASA

the correct answer is option d. none of these. it is noted that options a, b, and c share the same content.

despite the valid answer provided at the last sentence of each of the options, a question/answer format shouldn't include humourous themed responses such as "you bet your thermal pj's we do." - unless of course, the answer is carried out in an informal environment. this could be replaced with a simple "yes" or "it is necessary".

the question should be re-phrased to a more appropiate syntaxis. instead of "do we need the greenhouse effect? ", it should be written as "is the greenhouse effect necessary? " in order to give it a general scope, instead of limiting the answer to the needs of "we" the humans.