In Principle, Why Are T-Statistics and Critical Values Not as Useful

Multiple Choice

In principle, why are t-statistics and critical values not as useful in the practical construction of confidence intervals in most applications?

A) Their use is only valid in large samples.
B) Their use is only valid in small samples.
C) They are not often found in most software applications.
D) In large samples (i.e., large degrees of freedom) the t-distribution and standard normal distribution are very similar.