Correct option is D
Removing physical barriers in a school's infrastructure is a step towards inclusion. Inclusion in education refers to a model wherein students with special needs spend most or all of their time with non-special needs students. It implies adapting the environment to accommodate the needs of all students, ensuring they have equal access to education and school facilities. This differs from mainstreaming, integration, and exclusion, as inclusion specifically focuses on adapting the environment to meet the needs of all students, rather than expecting them to fit into pre-existing structures.