In a grinding operation, the limiting particle size is the size of the __________ particle in the sample.

Answer: Option B

In a grinding operation, the goal is to reduce the size of particles so that they all pass through a specified size limit.

The performance of the grinding process is judged by whether the largest particles in the sample are reduced to or below the target size.

Therefore, the limiting particle size in a grinding operation is determined by the size of the largest particle in the sample, since this dictates the extent of grinding needed to achieve the desired fineness.

If the largest particle is still above the required size, further grinding is necessary; hence, the largest particle size is the limiting factor.