The null hypothesis in ANOVA one-way classification, the study of the variances due to k different sources, is:

A

$$H_o: \sigma_1 = \sigma_2 = ...... = \sigma_k$$

B

$$H_o:$$ At least for one pair 

$$\mu_i = \mu_j; i,j = 1, 2, ...... k,$$ i ≠ j

C

$$H_o:$$ At least for one pair

$$\sigma_i = \sigma_j; i,j = 1, 2, ...... k,$$ i ≠ j

D

$$H_o: \mu_1 = \mu_2 = ...... = \mu_k$$