Which of the following numbers is a perfect square?

Since $70^2=4900$ and $75^2=5625$, any square here has a root in the seventies. A square ending in 6 must have a root ending in 4 or 6, and $74^2=5476$. The others sit strictly between consecutive squares: $73^2=5329$ < 5449 < 5476, 5625 < 5644 < 5776 and 5041 < 5100 < 5184.