Final answer:
The number of orbitals having the same principal quantum number (n) and shape as any given orbital depends on the type of orbital. There is one s, three p, five d, and seven f orbitals for each respective value of l, the azimuthal quantum number.
Step-by-step explanation:
In an atom, the number of total orbitals that have the same principal quantum number (n) and the same shape as a given orbital (such as orbital b or orbital c) depends on the azimuthal quantum number (l), which determines the shape of the orbital. For the s orbitals (where l = 0), there is only one s orbital per energy level. For the p orbitals (l = 1), there are three p orbitals per energy level. With d orbitals (l = 2), there are five d orbitals, and with the f orbitals (l = 3), there are seven f orbitals.
If orbital b refers to an s orbital, there would be only one s orbital for that value of n (so the answer would be none other than orbital b itself). If orbital b refers to a p orbital, there would be three p orbitals in total for that value of n (including orbital b, that leaves two orbitals identical to b). If orbital b is a d orbital, there are five d orbitals in the same energy level (including orbital b, that leaves four orbitals identical to b). Hence, the number of orbitals identical to a given orbital b (excluding itself) would depend on the type of the orbital: 0 for s, 2 for p, and 4 for d.