Final answer:
Consciousness must not be a physical property in order for it to not be infinitely fragile.
Step-by-step explanation:
The author suggests that consciousness must not be a physical property in order for it to not be infinitely fragile.
This is because physical properties are subject to change and can be influenced by external factors, whereas non-physical properties are not.
If consciousness were not a physical property, it would not be susceptible to being destroyed or altered by physical changes in the brain or external factors.
Therefore, option b. Consciousness must not be a physical property is the condition suggested by the author for consciousness not to be infinitely fragile.