The correct answer is A. Therefore
Explanation:
In writing, a transitional expression is a word or set of words that show the relationship between ideas or points and therefore help the writer and reader move from one idea to the following. Transitions are often classified depending on the type of relationship they indicate and because of this there are transitions of order such as first, second, finally; transitions of addition such as also or additionally; transitions of examples such as for example or for instance; and also transition of result and cause that include the words because, as a result, thus, therefore, among others.
This means the one that indicates a result or cause is "therefore" because this is a synonym of as a result or consequently and one of the main transitions that can be used to show the result as in the sentence "It was raining. Therefore, we could not go to the park" in which "therefore" show the result or consequence of the first sentence.
