"The new soldier misses the meal because of his officer."
Translation:החייל החדש מפספס את הארוחה בגלל הקצין שלו.
In multiple choice, since the sentence talks about "his" officer, I assumed the feminine option shouldn't be chosen. Yet I am marked wrong for that.
Yeah so he could miss his officer so much and could be depressed and so then miss a meal.
No. Note that this is not just "because", which requires a subordinate clause after it, but "because of" which doesn't.
In order to use כי, tge sentence would need a different ending, something like:
"... because his officer wanted to talk to him"
... כי הקצין שלו רצה לדבר איתו.