The construction of the t-statistic for a one- and a two-sided hypothesis:
A. depends on the critical value from the appropriate distribution.
B. is different since the critical value must be 1.645 for the one-sided hypothesis, but 1.96 for the two-sided hypothesis (using a 5% probability for the Type I error).
C. is the same.
D. uses ±1.96 for the two-sided test, but only +1.96 for the one-sided test.