Performance$-$based acquisition $($PBA$)$ is useful in PSP because it:

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a$.$ Allows entities to procure concentrating on what is required $($i$.$e$.,$ results$)$ as well as how the items will be procured $($i$.$e$.,$ process$)$

b$.$ Allows entities to procure concentrating on what is required $($i$.$e$.,$ results$)$ instead of how the items will be procured $($i$.$e$.,$ process$)$

c$.$ All of the above

d$.$ None of the above