B. verge - "On the verge of" means close to experiencing something, in this case, extinction.
Hadn't he - This is the correct question tag for the past perfect tense ("He'd finished").
B. was reading - This describes a continuous action happening at a specific time in the past, parallel to "was cooking".
A. I'm afraid we can't - This is the most appropriate response given the negative information about the weather.
A. more convenient - This is a comparative sentence, and "convenient" is a longer adjective, so "more convenient" is used.
A. application - In this context, "application" refers to a software program or tool, which fits the sentence's meaning.
C. clean up - "Clean up after someone" means to tidy the mess they have made.
B. to be sold - This sentence needs the passive infinitive form ("to be + past participle") to express that the house is receiving the action of being sold.
A - Since we are talking about any house and not a specific one we use the indefinite article "a".
B. change - "Change" refers to the money returned after paying for something with a larger amount.