In theory there is a difference insofar as an extended partition requires two LBAs (the MBR plus the first sector in the extended partition) to be written to once, and to be read subsequently on every mount. A primary partition only requires one LBA (the MBR).
So, strictly speaking, in terms of data security, a primary partition is 50% less likely to fail. In practice, 1/1015 and 50% of 1/1015 are pretty much the same. So, do whatever you like. But why not just use a primary partition if there's only one partition on the disk so far! There's no reason not to go with a primary partition, really. Saves you one useless disk seek on mount.
When setting up completely from scratch (which is not the case from the wording of your question, since you want to assign drive letter
D:, so that's not an option), you might consider GPT.
That will only work if you have a reasonably recent computer and operating system, but in that case it will have some (minor) advantages. The most important advantage is that you can have partitions larger than 2 TB and you can boot Windows in UEFI mode (presumed all other preconditions hold).
Note that contrary to urban myth, GPT is not necessarily much safer than MBR. While GPT does store a second GPT table at the end of the disk which sounds just great, it also requires at least twice as many LBAs to work, which again doubles the rate of unrecoverable read failures. So... at the end of the day, it's pretty much the same.