The diagram shows the electric field lines around two charges. based on the field lines, what is the best description of the charges ? a.) they are negative, and they repel b.) the left is negative and the right is positive, so they attract. c.) the left is positive and the right is negative, so they attract. d.) they are positive, they repel

The law of charges states that, like charges repel while unlike charges attract.
It is also important field lines move from positive to negative. 

From what we can see in the diagram, the field lines are moving away from the 2 charged particles  p and q. This tells us that the two charges are positively charged. 
Since, the two charges are having the same charge, they repel.

The best description of the charges is,   D.) they are positive, they repel