A thesis statement is a single sentence that puts together the main idea of any argument; it summarizes a topic and states a position on it. Expressing an argument, stating clearly what it is what you want to convince the reader about must be in the thesis statement.
This is not present in C .Frankenstein's monster killed Frankenstein's wife in revenge for the destruction of his mate is B Too Vague. The reasoning for this conclusion is missing. Revenge appears as a theme is Mary Shelly´s Frankenstein as it is made clear when Frankenstein's monster killed Frankenstein's wife infuriated after destruction of his mate.