I think the answer is although
Metaphor - it compares two things that are not alike
In general B is correct. For example, you would use this if you are asking Mayor Cortez to add a speed limit sign on your street.
If you are writing a social business letter e.g inviting Mayor Cortez to your house for tea, you may use C.
<span>Sir Tristram and Sir Marhaus both died as a result of their battle.</span>
