. As is often said, knowledge is power, and power in the wrong hands can be dangerous. ... If you yourself are faced with an opportunity to gain knowledge and later apply it, you must decide whether the potential benefits are worth any harm that may be done as a result.
Answer:
A
Explanation:
A is true. B is false because you can use more than one, depending on the structure of the sentence. C is false because of grammar rules, and D is false because you can indeed use both, depending on the structure of the sentence.
The word that serves as a clue of cause and effect is "Since".
