true
Each electronic shell in an atom is composed of subshells, which are denoted by the symbol s, p, d and f. These subshells are represented by the principal quantum number (n) and the azimuthal quantum number (ℓ).
Each subshell can hold a fixed number of electrons, which is equal to (4ℓ + 2) electrons.
For, d subshell the value of ℓ = 2.