Indicate which test (paired samples (ie dependent) t-test, independent two samples t-test, one sample ttest, independent samples z-test) is most appropriate for the following situations: A. Comparison of weight gain of two groups of 18 cows where one group was raised following standard practices and the other group was raised following "organic" standards.

B. Comparison of scores on a fitness test of Olympic-class distance runners (n=20) with the national average score of people of a similar age range (22-31 years).

C. Comparison of speed of texting on a smart phone of 20 teenager students compared to one of their parents.

D. Comparison of speed at texting of 24 Trent students using the hand they write with versus their other hand.

E. Comparison of body weights of 50 Trent students who identified themselves in a survey as "normally athletic". Weights were recorded just before and three months into the Covid-19 lockdown.