Answer:
D. Opposition.
Step-by-step explanation:
Opposition is the best configuration to view any of the outer planets (Mars and beyond). Opposition occurs when the Earth is directly between the sun and the outer planet, putting the planet at its closest distance to Earth. During opposition, the outer planet is visible all night, appearing brightest and largest in a telescope. Mars and Jupiter are frequently observed during opposition. Aphelion refers to the point in a planet's orbit when it is farthest from the sun, whereas conjunction is when the planet is in line with the sun and elongation is the angular distance between the sun and a planet, as seen from Earth.