Answer: C) Whatever his faults, Vondermoot can always be counted on for a seamless story that captures readers’ attention from page one.
Explanation: the tone of a sentence or a text is the author's or speaker's attitude towards the audience, the subject or even the characters. An objective tone, is a tone that expresses facts and doesn't express the speaker's opinion. From the given options, the one that represents a mostly objective tone is the corresponding to option C, because the other ones express strong opinions (like "eerie masterpiece", "spine-chilling situation" and "who are by far the best literature fans in the world").
It is a "limited Third-Person" type of narrator who has full knowledge of only one character, rather than all the characters, since they have no way of seeing other events outside of their own.