The expected value of sample information $($EVSI$)$ is the difference between

A the posterior probabilities and the prior probabilities of the states of nature

B the expected payoff with perfect information $($EPPI$)$ and the expected monetary value for the best decision $($EMV$*)$

the expected monetary value with additional information $($EMV$\text{'})$ and the expected monetary value for the best decision $($EMV$*)$

D the expected value of perfect information $($EVPI$)$ and the smallest expected opportunity loss $($EOL$*)$