3 . We were at a disadvantage that we weren't too familiar with the language the others were using. - by
- with
- for
- in

We were at a disadvantage in that that we weren't too familiar with the language the others were using.

Explanation:

In the given sentence, the correct preposition to be used is "in". This is because "in" will introduce the argument or provide an explanation for the statement before the blank.

With the use of "in", the statement "we weren't too familiar with the language the others were using" provides an explanation for the first statement "[W]e were at a disadvantage". Whereas the use of the prepositions "by", "with", and "for" are incorrect.

Thus, the correct answer is "in".

i believe that the answer is b! i hope i out!