Under the logic of hypothesis testing, if a researcher says "I have proven the null hypothesis false," what he/she means is

a. we know for certain that the null hypothesis is false.

b. we are unsure if the null hypothesis is false, but we know that the alternative hypothesis is true.

c. there is a 95% chance that the null hypothesis is false (for = .05).

d. we are unsure if the null hypothesis is false, but there is a 95% chance that the alternative hypothesis is true (for = .05).