Could you please help me understand why/how the correct answer is supported ? Thank you very much !

A chi-square test comparing a baseline logistic regression to a logistic regression M adding additional predictors has k degrees of freedom under the null hypothesis. Save What determines the value of k? Correct Answer O A) The number of additional variables added to the second model O B) The number of total variables in the baseline model You Answered O C) The number of total variables in the second model O D) The number of constants in the 2nd model O E) The number of categories the outcome variable could take