Answer: The correct answer for the blank is -
C. Supplies are becoming scarce.
Step-by-step explanation:
The term resource includes food, water, shelter, light, territory or any way that is required to maintain life of organsims and to reproduce.
Supplies in terms of resources are getting scarce day by day, therefore competition for resources (between organsisms of the same species or different species that share similar resources) will intensify that is it will become more.
Thus, option C) is the right answer.