Identify the correct statements about Schaefer-Hartshorne debate.

A. For Hartshorne, geography is what geographers have made it while Schaefer worked on what geography should be.

B. Schaefer promoted the study of areal differentiation while Hartshorne favoured exceptionalism in geography.

C. Schaefer advocated for formulation of laws in geography.

D. Schaefer was against the application of positivist methods in geography.

Choose the correct answer from the options given below.