What happens to the diaphragm muscles during the process of inspiration?

Which one of the following is a possibility for most of us in regard to breathing,by making a conscious effort?

Which muscles help us to increase the strength of inspiration and expiration?

Air moves into the lungs when

Select the correct events that occur during inspiration.
$(a)$ Contraction of diaphragm
$(b)$ Contraction of external inter-costal muscles
$(c)$ Pulmonary volume decreases
$(d)$ Intra pulmonary pressure increases

Breathing involves ...$A$... during which atmospheric air is drawn in and ...$B$... by which the alveolar air is released out.
Choose the correct option for $A$ and $B$ to complete the given $NCERT$ statement.