【单选题】When is the t- distribution the appropriate distribution to use The t -distribution is the appropriate distribution to use when constructing confidence intervals based on:
A.
small samples from populations with known variance that are at least \r\napproximately normal.
B.
large samples from populations with known variance that are \r\nnonnormal.
C.
small samples from populations with unknown variance that are at least \r\napproximately normal.