In the passage, slumbering means rejoicing, because Winter "wears on his smiling face a dream of spring". Winter is smiling, therefore he must be rejoicing. Hope this helps!
Example
1. Apples tast
2. Books cover
3. Houses roofs
I think this is an example of divine intervention
Something that works and something that is useful
Well, unencumbered in this question means not "tied down" or restricted.
So the answer is A.
Explanation: The horse was freed from its restraints as it galloped around said open field.
