The context of your question isn't clear, but if you're asking which of these could potentially occur as a consequence of population growth or changes in an environment, then the correct responses could be:
- a: An increase in survival rates (if resources are managed well)
- b: An increase in available resources (if innovation or management improves resource availability)
- c: An increase in resource competition (which is typical in growing populations)
- d: An increase in the spread of disease (as populations grow closer together)
However, depending on the specific context of your inquiry, the correctness could vary. If you could clarify the context, I would be better able to provide the appropriate responses.