During a project closing, problems with readiness or impact are evaluated.

Which of the following project issues below is an issue with impact?

a$.)$

State law changed to require $12$ in$.$ of material under a playground; there is only $10$ in$.$ provided.

b$.)$

The walking trails in the park were gravel, yet many local people prefer well$-$groomed, paved trails.

c$.)$

The pump for the fountain in the main water feature is on backorder.

d$.)$

The lights in the park shelter need to be connected to the electrical system.