What's it like

B is perfectly correct, especially if the gender of the dog is not known.

Oh, thank you Philip. Then the following conversation between A and B is correct. Then how can A answer to B's question when he asks .... Oh, What's it like?

A: I have got a new dog.
B: Oh, what's it like?
A: --------------------------------------------.
?

I would then use a gender specific pronoun: Oh, he's really cute; she's a little love; she's learning quick; he's really smart; he's just the right size...

PhilipI would then use a gender specific pronoun: Oh, he's really cute; she's a little love; she's learning quick; he's really smart; he's just the right size...

Thank you Philip. Is it also correct if A answers like the following ......

A: I have got a new dog.
B: Oh, what's it like?
A: It's really cute but aggressive.
?

Certainly. The use of the gender specific pronoun/adjective is always optional. I think that with domesticated animals it is more often used, however.

Thank you, Philip. Probably the following conversation is also correct. Right?

A: What's your dog like?
B: It's really aggressive.
?

Thank you, Philip. Probably the following conversation is also correct. Right?

A: What's your dog like?
B: It's really aggressive.
??

It's correct.