Concept:A p sub-level is defined by azimuthal quantum number l=1 and contains a fixed number of orbitals based on allowed magnetic quantum numbers.Explanation:For a p sub-level, l=1.The magnetic quantum number ml can take values from −l to +l, which gives ml=−1,0,+1.Each distinct value of ml represents one orbital.Since there are three possible ml values, the p sub-level has three orbitals.These orbitals are conventionally labelled px, py, and pz.They have identical energy but are oriented along different axes in space.Answer:The correct answer is B. 3.