Which of the Following Statements Is True for Chi-Squared Tests

Which of the following statements is true for chi-squared tests?

A) Testing for equal proportions is identical to testing for goodness-of-fit.
B) The number of degrees of freedom in a test of a contingency table with r rows and c columns is (r - 1) (c - 1) .
C) The number of degrees of freedom in a goodness-of-fit test with k categories is k - 1.
D) All of these choices are true.