I have asked 3 Hindi speakers what Hindi for "socks" is. No one came up with जुराब. Only one even knew any word at all. It seems to me that learning the word "socks", which is not a common Hindi word, is not a good use of our time. Can we not learn a clothing word we will use more often and that native speakers will recognize? With this said, Kudos to Duolingo for a great course.
My wife who is a native speaker always prefers to use "socks", and so do most native speakers I know. As far as I know, there are two words for "socks", जुराब and मोज़ा. Both are loanwords from Persian/Arabic. However, it seems that जुराब is most commonly used to mean "knitted socks" in particular while मोज़ा commonly means "stockings".