1) (C) At first you may find it odd that "another" is used before 10, as you would expect it to be used with the singular form. However, 'another' can be used before a plural noun when there is a number before that noun.
Example": I've already spent 100 dollars in the Casino, and I'm afraid I'll spend another 50 tonight.
2 (B) This is a little trickier. 'The others' usually refers to 'The other people'. Since it seems like Mary is talking about THINGS (not people), I would choose the pronoun 'others', without 'the'.
Hope it was helpful! ;)