"C", "Maybe".
The credibility depends on the websites contents and credentials.
A website like a government's page is considered, "credible", because it is from a trusted source; the government. Whereas getting a random answer from Yahoo is considered less credible because of it not stemming from a trustable source.
Hey, it's TeenSuicide.
Fog rolling down the river is a form of figurative language known as personification. Personification occurs when a non-human object is given a human characteristic or action. In this case, fog cannot literally "roll" down the river. I mean, just imagine a person rolling down a hill like a derp-head. Fog doesn't do that, but in a figurative way, it "rolls" down the river. I hope you can understand :')
I believe the answer is B