The sentences are: "And my advice to all people is, Don't stay at home any more than you can help; but when you have GOT to stay at home a while, buy a package of those insurance tickets and sit up nights. You cannot be too cautious."
Irony is defined as stating the opposite of what is intended and it usually has a humorous effect.
C and D I think either could work. Moreover D though.
When the narrator refer Mr. Brympton as "that kind of gentlemen", she mean that se does not trust Mr.Brympton.
You can find in the excerpt that the author said 'the typhoid has served me well" before the sentence, which mean that she want Mr.Brympton to paid no attention to her
hope this helps
Participles are verb forms which look like verbs + suffix -ing. So having that in mind, the participle in the sentence above is the word standing.
Participles function either as adverbs (when they modify verbs), or as adjectives (when they modify nouns). In this case, the participle acts as an adjective, modifying the word child.