Answer :
The most appropriate test to be used here would be a b. A one-sample t-test for a population mean.
Reasons to use one-sample t-test for a population mean.
One sample t-test is used when one wants to compare the mean of a population to another mean for statistical difference which is what the researchers hope to do here in comparing the mean battery life of a new battery to an old one.
A population mean will also be used because the population standard deviation is not given.
In conclusion, option B is correct.
Find out more on sample t-tests at https://brainly.com/question/6501190.