PLEASE HELP Read these lines from "To Autumn."

Season of mists and mellow fruitfulness,
Close bosom-friend of the maturing sun;
Conspiring with him how to load and bless
With fruit the vines that round the thatch-eves run;

What does the phrase "Close bosom-friend of the maturing sun" mean?

The sun and autumn work together like loving companions.

The sun and autumn are literal individuals who care about each other.

Autumn is the only season the sun likes.

The sun begins to retreat as autumn progresses.