When is it appropriate to use the​ two-sample t-methods instead of the one sample​ t-methods? Choose the correct answer below. A. Use the​ two-sample t-methods when a sample was taken from each of two populations​ (i. e. two groups being​ compared) and the population standard deviations are not known. Use the​ one-sample t-methods when a sample was taken from one population. B. Use the​ two-sample t-methods when a random sample was not taken. Use the​ one-sample t-methods when a random sample was taken. C. Use the​ two-sample t-methods when the conditions for inference using the​ one-sample t-methods​ aren't satisfied. D. Use the​ two-sample t-methods when the population standard deviation is known. Use the​ one-sample t-methods when the population standard deviation is not known.