Which Teacher Is Using Seatwork Most Appropriately

Which teacher is using seatwork most appropriately?

A) Mrs.Wiggins gives students a worksheet to complete independently.It introduces the new concept for their work at centers.
B) Ms.Cranfield gives students a word puzzle to complete at their seats.They just finished reviewing the vocabulary words for the integrated reading and writing unit.
C) Mrs.Gomez precedes group work with a worksheet for students to do at their seats.It explains how to approach a new kind of math problem.
D) Mr.O'Malley gives students an independent assignment in their science workbooks.It asks questions about the material he will lecture on tomorrow.