Because you still get a upper case B in all of them. The dominant takes over the recessive because there's a dominant trait in all of them.
Bb Bb Bb Bb.
If you want to see for yourself, get a piece of paper and a pencil and draw 4 squares on it then write two uppercase B's on the top (or on the side) and two lowercase b's on the side (or on the top). You should get Bb for all of them. Since all of the boxes have at least ONE uppercase letter, it's homozygous. Also, if i remember correctly, homozygous is one uppercase and a lowercase letter together and that makes a dominant trait. Or it can be two uppercase letters (BB) or two lowercase letters (bb). I hope this helps!
