The inner transition element in the following is.....

The correct answer is Option (3) → Ce

Inner transition elements are the f-block elements, in which the last electron enters an (n−2)f orbital. They form two series placed below the main periodic table:

• Lanthanoids (4f series): the fourteen elements after lanthanum, from cerium (Z = 58) to lutetium (Z = 71).

• Actinoids (5f series): the fourteen elements after actinium, from thorium (Z = 90) to lawrencium (Z = 103).

Cerium (Z = 58, [Xe]4f¹5d¹6s²) is the first lanthanoid, so it is the inner transition element.

NCERT (2026-27 edition):
The d- and f-Block Elements – …