WHat would grammatically fit here?
The president of the United States appoints the cabinet members, _________ appointments are subject to Senate approval.
The correct answer would be letter D. If the sentence is read and each option is tried, 'but their' is the only one to make sense. Furthermore, answer A is only a possessive and to use answer A would require different punctuation.
Answer B isn't a sentence connecter which is important because these two thoughts could be written as two separate sentences. Answer C includes the word 'because' which would imply a reason for the first part of the sentence.
There is a full sentence (subject+verb) before the comma. After the comma there is subject, verb and complimentary phrase. This means a connector is missing.
1. It is not (A) because it is only a possessive.
2. It is not (B) because with is not a sentence connector.
3. It is not (C) because the second sentence is not a reason to the first.
4. It is (D).