Hi,
@mrblack - Only the word "dispose" does not mean "to throw away". Why we believe it to be that way is because we use this word in our day-to-day speech in that manner and hence, we think that this is the correct meaning and the correct usage. But that is not true. "Dispose" has multiple dictionary meanings:
1. to give tendency or inclination to: Lack of basic amenities disposed the residents of that area to look for another alternative.
2. to put in a particular or suitable place: At the end of the class, Harry was asked to dispose all the writing books in shelves.
3. to put in a particular or the proper or arrangement: The sports captain asked Amy to quickly dispose her team that would represent their school in inter-school basketball tournament.
4. to make fit or ready; prepare: My preparation has disposed me to confidently take the GMAT.
If we want to use the word "dispose" to mean "throw away", then we have to use it with the preposition "of". Together they make the sense of "throw away".
Example: My mother disposed of all the left over food that was kept on the table.
It is not uncommon to see certain verbs being used with specific prepositions to have a specific meaning.
Examples: 1. Mary has
put on a lot of weight. OR Mary had put on so much of make up that it looked bizarre.
2. The teacher
put off the dates of examination for the third time in this month.
So, now it is easier to see why choice A is the correct answer.
Thanks.
Shraddha