To determine the maximum number of houses that can be built in the town, you multiply the maximum density of houses per block by the number of blocks.
The maximum density of houses per block is 12, and there are 23 blocks.
So, the calculation would be:
\[ 12 \text{ houses/block} \times 23 \text{ blocks} = 276 \text{ houses} \]
Therefore, the correct answer is 276 houses.