A. The ‘secret ministry’ of the frost is that:
(d) it has a secret deal with nature.
Samuel Taylor Coleridge uses the word "ministry", which conveys something is working on behalf of others. It may have a religious connotation as well, as minister can also mean pastor. So the author wants to express nature as something that is alive, which is why it can have a deal with the frost. And it is secret because it falls at midnight, when everyone is asleep.
B. There is silence all around. This is seen in the phrase:
(b) all at rest.
The author says everyone else is sleeping, so aside from the owl breaking the silence twice, there is no other sound.
C. Who is sleeping in the cradle?
(c) the poet's son.
His son Hartley is the one sleeping, which is clear in the sentence "my cradled infant".
D. What disturbs the calm?
(c) the calmness.
Coleridge expresses that the calm is so deep that it is disturbing in itself in the verse:
"‘It’s calm indeed ! so calm, that it disturbs
And vexes meditation with its strange
And extreme silence."
E. The word ‘meditation’ means:
(b) deep thoughts.
The author is referring to his tendency to get lost in deep, philosophical thoughts, which he is able to do when he is by himself at night and everything is quiet.
