Translation:I carry my younger sister's bag.
I can't check your source because for some reason I can't click the link in the app, but based on wikitionary it comes from ancient Chinese. However words that come from ancient Chinese are not considered loanwords, especially if they have kanji - which カバン does have - 鞄. かばん can also be written in hiragana as was done in another exercise here. Apparently it can be written in katakana to "convey a less formal tone of conversation".
Interesting, seems like there is a bit of contradiction between your source (which I managed to open now) and wikitionary. Wikitionary says the word comes from Chinese 夾板 (pinyin jiābǎn) but it doesn't seem related in meaning. Seems more likly it is a loanword, as your source says some older loanwords were given kanji too.
It is related to ancient China's stuffs. I am not sure, but if it DOES originate from Chinese, that makes sense... 夾板 means boards for holding things.
According to an idiom 负箧曳屣, in ancient China, we use wood splint to make something like a box to carry books... 负 means to carry; 箧 means a box, a trunk; 曳 means to pull, drag; 屣 means shoes. The idiom means to carry a heavy box (filled with books) and drag his shoes (because his shoes are worn out and cannot bind his feet). It depicts a poor scholar dedicated to pursuing knowledge.
But anyway, 鞄 and 夾板 have totally different meanings and they both seem rarely used in modern Japanese...
My answer was "I carry my little sisters bag" and I got it right but was told
"You have an extra space.
I carry my little sister s bag."
?? The correction told me I had an extra space and actually added a space that wasn't there. I assume it's my lack of apostrophe that confused it but it has never marked punctuation things before, and the corrected answer is the complete opposite of what it says my error is? Duo what are you even talking about lol
No, someone else's sister is いもうとさん。 Here is a chart showing the different words used for one's family versus others' families. https://www.learn-japanese-adventure.com/japanese-family.html You can't click on the link to get there, but it works if you paste it in the browser.