D block Elements are Transition Elements
D block elements are the elements which can be found from the third group to the twelfth group of the modern periodic table. They are called so because the last electron enters the d-orbital.
Transition metals are actually a subset of d-block elements.
For an element to be called transition metal, it should have partially filled d-subshell.
If we look at the electronic configuration of Zn, Cd and Hg all of them have filled d-orbital.
So, these are d-block elements but not transition elements.