In the context of the scenario described, the most likely explanation for the differences in the depth of the hole made by each student's object is that Naveed's object had greater kinetic energy.
When dropped from the same height, an object's kinetic energy just before impact is primarily determined by its mass and the height it was dropped from, according to the formula for gravitational potential energy (PE = mgh), where 'm' is mass, 'g' is the acceleration due to gravity, and 'h' is the height. If Naveed's object has either greater mass or greater volume, it would have more kinetic energy upon impact, causing it to displace more sand and create a deeper hole compared to Maddie's object.
The other options do not explain the depth of the hole as effectively: the width of the object and drop speed alone do not determine the kinetic energy without additional context regarding their mass and shape. Therefore, Naveed having greater kinetic energy is the most likely explanation for the observed results.