Simple Multicellular Organisms That Are Small Can Meet Their Gas

Simple multicellular organisms that are small can meet their gas exchange needs by means of:

A) a flattened body shape that increases their surface area
B) a flattened or thin body shape that reduces the distance between cells inside their body and the external environment
C) by living in air that provides abundant oxygen, even though they are at risk of losing water and drying out
D) by living in water so that they do not dry out from water loss, even though water has less oxygen per volume than air
E) by relying on anaerobic respiration (glycolysis) for long time periods, so that they don't need to use oxygen for aerobic respiration