Is this a trick question?

Rowan and I were reading one of his counting books (Margaret Wise Brown's "Count to 10 with a mouse" which was given to him by his Great-Nanny) a couple of nights ago.  This has become quite a regular read lately, and Rowan loves asking about the pictures on the pages.

This is a lovely book with a good rhythm:

'There was a little mouse, no bigger than a mole

who lived in a round place that he called a hole'

Number 6 is illustrated with six cats playing with some wool. Rowan pointed at each cat and said "that one?" which is his version of asking "what's that?"  The conversation went as follows:

Rowan: "That one?"

Me: "That's a cat."

Rowan: "That one?"

Me: "That's a cat."

Rowan: "That one?"

Me: "A cat."

Rowan: "That one?"

Me: "That's another cat."

Rowan: "That one?"

Me: "That's a cat."

Rowan: "That one?"

Me: "What do yo think it is?"

Rowan: "Cheese."

I'd love to understand the logic of a toddler.