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

Which of the following statements is true for the chi-squared tests? $\begin{array}{|l|l|}\hline \text { A. } & \text { Testing for equal proportions is identical to testing for goodness-of-fit. } \\\hline \text { B. } & \begin{array}{l}\text { The number of degrees of freedom in a test of a contingency table with } r \text { rows and } c \\\text { columns is }(r-1)(c-1) \text {. }\end{array} \\\hline \text { C. } & \text { The number of degrees of freedom in a goodness-of-fit test with } k \text { categories is } k-1 . \\\hline \text { D. } & \text { All of these choices are correct. } \\\hline\end{array}$