To what extent is Medea a sympathetic character?

You could really argue this either way provided you made a strong argument supported by examples from the text. However, I would expect a more nuanced answer to explore both sides of the argument and to think about how Medea’s character develops throughout the play. Remember that a ‘to what extent’ question is encouraging you to look at this argument from both sides and to make it clear what your personal opinion is. Does Medea deserve our sympathy or not?
One key thing to consider in terms of Medea being unsympathetic is her actions – Medea kills her children, an act horrifying to both modern and ancient audiences. It is, of course, hard to sympathise with someone who behaves in this manner. Medea uses her children to hurt Jason and then kills them even though they are innocent. However, you could argue that we feel some sympathy for her because of her circumstances. She is far away from home, isolated and now feels abandoned by Jason. Medea is desperate and therefore not acting in a rational manner.
There is really no right or wrong answer here since the question is asking for your opinion. Just remember to consider both sides, make it clear where you stand on this argument, and back up your points with examples from the text.