What is a central idea of "Mending Wall"? The speaker thinks his neighbor is misguided in his views of the purpose of walls and fences.

Two neighbors form an important bond while repairing a wall.

The speaker and his neighbor agree to work on a property wall silently because they cannot agree.

The speaker and his neighbor meet to rebuild a wall and talk about the different forces that bring walls down.

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.

it can make them lose love for themselves

c is the answer because first she would blush to make the reader wonder why which they find out in the next line.