According to the e$-$learning handbook by the American Society for Training & Development, blended learning is defined as

a the dependency on virtual tools to simulate a classroom environment.

b the adoption of digital tools to address more than $50\%$ of a classroom curriculum.

c the use of three or more distinct methods of lsaining.

d the use of two or more distinct methods of training.

e O Leave blank for now. I'Il submit my answer later.