KPSS 2018-1 Soru=23

Over the years, language teachers have alternated
between favouring teaching approaches that focus
primarily on use and those that focus on language
forms and analysis. The alternation has been due to
a fundamental disagreement concerning whether one
learns to communicate in a second language by
communicating in that language or whether one learns
to communicate in a second language by learning the
words and grammatical structures of the target
language. ---- It is not uncommon to find learners, who,
for whatever reason, find themselves in a new country,
who need to learn a new language, and who do so
without the benefit of formal instruction. In contrast,
there are learners whose entire exposure to the new
language comes in the form of classroom instruction in
lexicogrammar.

Which of the following completes the paragraph
coherently?