Which statement is true about the transitions because and as a result in the following sentences
Amir reached his savings goal because he worked hard at his new job all summer. As a result, he was able to buy the new skates that he wanted.
A. Both because and as a result signal a cause.
B. Because signals an effect and, as a result, signal an effect.
C. Both because and as a result, signal an effect.
D. Because signals a cause and as a result signals an effect.