The correct answer would be alternatives:
A)"Overexposure of candidates.". The internet exposes all of the information on all of us, specially social media. With the internet, any controversial event that might harm the candidates will be known to everybody in seconds.
B)"Misinformation.". Nowadays, Fake News are a huge problem. People with bad intentions create fake news, and most people don't even fact check articles before sharing them and believing in the headlines. This causes people to be misinformed about events. Another possibility is journalistic bias, when a journalists bends the story according to their personal beliefs.
C)"Partisan Dialogue". According to the dictionary, Partisan means Prejudicial. Prejudicial Dialogue on the internet can be understood as discussions that focus more on the individuals' beliefs or personalities rather than on the information being discussed. It's harmful due to the proportions they can get, and because anyone can initiate a partisan dialogue anytime about anything.