The central atom/ion of a coordination entity is also referred to as a

The correct answer is Option (1) → Lewis acid

NCERT (2026-27 edition):
5.2 Definitions of Some Important Terms Pertaining to Coordination Compounds – “In a coordination entity, the atom/ion to which a fixed number of ions/groups are bound in a definite geometrical arrangement around it, is called the central atom or ion. … These central atoms/ions are also referred to as Lewis acids.”