The classroom is replaced by subject lab in:ABiographical methodBDiscovery methodCDalton planDLecture methodAnswer: C. Dalton plan Read Explanation: The Dalton Plan is a progressive educational model created by Helen Parkhurst in the 1920s in Dalton, Massachusetts, USA.Parkhurst developed a three-part plan that continues to be the structural foundation of a Dalton education: House, Assignment, and Lab.The Dalton Plan is a method of education by which pupils work at their own pace, and receive individual help from the teacher when necessary. There is no formal class instruction. Students draw up time-tables and are responsible for finishing the work on their syllabuses or assignments. Read more in App