The randomized block design with exactly two treatments is equivalent to a two-tail:

A) independent samples z-test
B) independent samples equal-variances t-test
C) independent samples unequal-variances t-test
D) matched pairs t-test
E) independent samples t-test

The randomized block design with exactly two treatments is equivalent to a matched pairs t-test because it involves pairing each subject in one group with a subject in the other group based on some blocking variable (e.g. age, gender, etc.) and comparing the two treatments within each pair. Therefore, the best choice is the matched pairs t-test.