What is XBT vs CTD?

Could you please elaborate on the distinction between XBT and CTD in the realm of cryptocurrency and finance? I understand they are both related to Bitcoin, but how do they differ in terms of their usage, functionality, and perhaps even their underlying mechanisms? Are there any particular scenarios or applications where one might be preferred over the other? I'm seeking a clear and concise explanation to help me better grasp the nuances between these two terms.