There appears to be a mistake in one of the quiz answers. This is in the RH124 material for RHEL 8, Chapter 3, section 4
The second option is cd.. -- which is not a Linux command (works in Windows, though). Now, with this question, it is also NOT the correct answer.
Even so, cd.. does not appear in any of the other questions. The correct form, cd .. (with the space), does.
The spacing issue appears to be specific to the RHA material and does not appear in the Red Hat Learning Subscription version of RH124.
I think the answers might run into accessibilty issues for the visual impaired by being too similar. I would rewrite them this way. There are two correct answers now.
B. cd ~/
C. cd /home
D. cd /user
The last two answers test if the student understands the Linux FSH.