What is a plausible explanation for why bacteria lack ether-linked cell membranes?

Options are not provided in the question. The complete queston is as following:

What is a plausible explanation for why bacteria lack ether-linked cell membranes? Select one  

a. They need chitin in the cell membranes

b. They exchange fluids with the environment

c. They do not live in the extreme environments

d. They have peptidoglycan in their membrane

c. They do not live in the extreme environments

Explanation:

The cell wall in bacteria (Gram-negative Bacteria) is made up of a single layer of peptidoglycan surrounded with an asymmetrical lipid bilayer (lipopolysaccharide (LPS) together with a glycolipid)  called outer membrane. The cell membrane facilitate solute and protein translocation, as well as signal transduction.

Bacteri ado not posses ether-linked cell membrane because ether bonds are more thermostable and functions at high temperature only. In environment bacterial-type, archaeal-type, and mixed-type membrane lipids are majorly found.

So, as bacteria do not live in the extreme condition which is a prime requirement for the stability of ether-linked membrane, bacteria lack ether-linked membrane and have lipid membrane.

Hence, the correct otpion is c.

What appears to be another given is a plot relating the rate of heatbeat and time. Distance is the integral of speed with respect to time. This corresponds to the area under a v-t graph. Taking the height of the triangle to be 0.75m/s and the base to be 0.32s which gives distance of beat equal to  7.5cm