Answer:
The answer is "Option D".
Step-by-step explanation:
A line is a horizontal 1D-dimensional representation without any thickness and extends in every way. It sometimes is also known as the straight line. The line, which connects two planes lies simultaneously on both planes, that's why in this question only "option D" is correct.
The least common multiple of 18 and 42 is 126. Sorry I don't know how to explain it.