<p>D-clearance simply means you need to have department clearance in order to register for the class. This may be for various reasons such as in order to restrict certain people such as non-engineers in this case or a requirement to fulfill certain pre-requisites or co-requisites or for other reasons. You basically talk to the person at the front desk of the department and they will either put you in contact with someone who is in charge of it, and they will go on their computer and do some registration magic and then you are able to register for it normally. </p>
<p>Whoops, I meant “throw” rather than “through” but once again its a maybe and probably more a of a not likely. The material and book is the same for each section so you won’t be taught anything differently. You’re fine regardless of which section you choose as the difference (if any) is ultimately negligible in the end.</p>