'A cat' should be accepted too. Please use the 'Report a Problem' button next time you encounter this sentence. This course is still in beta, and sometimes correct answers are not accepted.
So the "у" anywhere in a sentence is always for the "have" setup? There is no есть or нет following... It totally threw me off. I was trying to figure out if it was suppose to be some new connecting word and so wrote "my butter and cats". Anyone care to elaborate on this particular set-up for me? Thanks.