Which of the Following Is the Correct Equation to Calculate $(\# \text { of rows - 2) } *(\text { \#of columns - 2) }$

Which of the following is the correct equation to calculate the degrees of freedom in a Chi-square test?

A) $(\# \text { of rows - 2) } *(\text { \#of columns - 2) }$
B) $(\# o f \text { rows }-1) *(\# \text { of columns - 1) }$
C) $(\# o f \text { rows - 2) }+(\# \text { of columns }-2)$
D) $(\# \text { of rows }-1) +(\# \text { of columns }-1)$