Regarding question 3,
What shall be done to option D so that it can be better than option E.
sl750 wrote:king and coral snakes is seen as one subject
kings and coral are not parallel, kings in plural and coral is singular
So A is correct
In question 2, 'the costs of traveling by public rail', cost, here is an uncountable noun. Had it mentioned other costs as well, then you can treat it as a countable noun. So D is correct here
In question 3, E is correct, the other choices have modifier issues
