On hot summer days, electricity-generating capacity is sometimes stretched to the limit. At these times, electric companies may ask people to voluntarily cut back on their use of electricity. On these days, electricity is: a. excludable, but nonrival in consumption.
b. excludable and rival in consumption.
c. not excludable and nonrival in consumption.
d. not excludable, but rival in consumption.

b. excludable and rival in consumption

Explanation:

For categorizing the goods as private or public, the two terms we need to understand i.e.  rivalry and excludability

The rivalry refers only one person could consume it no other has the right to consume the same thing

While on the other hand, the excludable arise when you stop someone from using a particular thing

So here in the given case, the option b is most appropriate as it is fit to the scenario

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explanation: