When the student learns in the new language but does not speak it for some time, this period is called the __________period.

Correct option is B

Silent.
The silent period is a natural phase in language acquisition when a learner understands and processes the new language but does not yet speak it fluently. This period allows them to internalize the language patterns and structures before attempting to express themselves orally. The other options, speech emergent, early production, and emergent, are not specific to the silent period in language acquisition.