Which describes the role of the diaphragm during inhalation?

a the diaphragm flattens, making the chest cavity smaller, and air is sucked in.

b the diaphragm moves upward, making the chest cavity smaller, and air is pushed out.

c the diaphragm flattens, making the chest cavity larger, and air flows in.

d the diaphragm moves upward, making the chest cavity larger, and air flows in.