Choice B is correct. It's given that $1 yard = 36 inches$ . Therefore, $612$ inches is equivalent to 612 inches$$(\dfrac{1 yard}{30 inches}), which can be rewritten as $\dfrac{612 yards}{36}$, or $17$ yards.

Choice A is incorrect, This is the number of yards that are equivalent to $2.124$ inches Choice C is incorrect. This is the number of yards that are equivalent to $20,736$ inches.

Choice D is incorrect. This is the number of yards that are equivalent to $793,152$ inches.