The correct answer is C. The letter shocked me.
A. They shocked me with the letter. This is incorrect because the letter is the subject of the sentence, not the object. The letter is what did the shocking, not the person who wrote it.
B. I am shocked. This is incorrect because it does not specify what the person is shocked about. The sentence could be interpreted as meaning that the person is shocked in general, or that they are shocked about something else entirely.
D. I shocked with the letter. This is incorrect because it is grammatically incorrect. The verb “shock” requires a direct object, and in this sentence, the direct object is missing.
The sentence “I was shocked by the letter” means that the letter surprised or upset the person in a significant way. The letter may have contained bad news, or it may have revealed something that the person did not know. Whatever the reason, the letter had a profound impact on the person.