The first sentence I believe
4️⃣Jane did not fill her car up with petrol before she left, <u>that</u> was careless of her.
5️⃣ They always give the available seats to <u>whoever</u> comes first.
6️⃣ A home computer <u>provides</u> an opportunity for convenient and efficient work at home.
7️⃣ Near the White House is another famous landmark <u>called</u> the Washington Monument.
8️⃣ There was a small room into <u>that</u> we all crowded.
9️⃣ I received two job offers, <u>neith</u><u>er </u><u>of </u><u>which</u> I accepted.
1️⃣0️⃣ I have three brothers, <u>two </u><u>of </u><u>them</u> are professional athletes.

Sparingly (adv) - In a manner where you only do something in spares— i.e. in small numbers/frequency.
Ex- if you have spare tires then you have extra. If you use the tires sparingly you’re trying to spare the tires—so you’re trying not to use it; you are sparing it. Use it only if you have to!
Use it in a sentence: Eating candy is usually bad for you, so eat it sparingly.
The Mousetrap is the name of the play that Hamlet presents to King Claudius.
Judging by how it's used in the context, I would say C. A great number.