Answer: Option D " decrease, more, decreasing"
Step-by-step explanation:
Pulmonary surfactant can be defined as the surface-active proteins which is made of type II alveolar cells. These surfactant is made of protein and lipids which are both hydrophobic and hydrophillic in nature.
It greatly reduces the surface tension in the alveoli, which make the lungs more compliant (ability of the lungs to stretch and expand) and hence, decreases the work required to inflate it.
Thus the correct answer is option D