The main idea would mainly be about what a spacewalk is and the steps they take to go on spacewalk
Your answer would be C. Hope this helps!
A.) lines 6-9
If the British march
By land or sea from the town to-night,
Hang a lantern aloft in the belfry-arch
Of the North-Church-tower, as a signal-light, —
One if by land, and two if by sea;
