Fill in the blank with the suitable determiner:

______ student in the class must wear winter uniform from today.

Every

The correct answer is Option (2) - Every

Every student in the class must wear winter uniform from today.

"Every" is used here to indicate each individual student in the class.
It is the appropriate determiner to express that all students, without exception, are required to wear the winter uniform.
 The other options ("more," "one," and "much") do not fit grammatically or contextually in this sentence.