In "where have you gone, charming billy? " why can't paul stop laughing at the thought of billy boy dying?
a). he feels that death in general is funnier than it's tragic.
b). he finds it ironic that billy boy died of a heart attack in a war.
c). he believes that billy boy deserved to die a more heroic death.
d). he knows that billyboy would've found it amusing to die that way.

covert: hidden or secret

candid: truthful and straightforward

what i get from these phrases is covert means undercover or underground and that's where the flower is in april. on the other hand, may is the month where flowers start to bloom and thats the reason why candid is being used as a word to describe the blossoming period of a flower.

hope this answer you.

- "when these words are put together to convey a meaning it is known as a sentence. a sentence is a group of words that makes complete sense. placing of words in a sentence is very important. the second sentence is a question."