To determine the correct IUPAC name of the given compound, we need to follow a systematic approach for naming spiro compounds.

1. First, identify the spirocyclic system and count the number of carbon atoms in each ring. The compound shows two rings connected at one carbon atom (spiro linkage). Count the number of carbon atoms in each ring excluding the spiro carbon:
   • One ring has 5 carbon atoms.
   • The other ring has 6 carbon atoms.
2. The spiro compound is named as “spiro[a.b]alkane,” where ‘a’ and ‘b’ are the number of carbon atoms in each ring, listed in ascending order (excluding the spiro atom). In this case, it is spiro[4.5].
3. Identify any substituents and their positions. The chlorine atom is attached to the carbon adjacent to the spiro carbon on the smaller ring (which has 5 carbons). Count starting from the spirocarbon to give substituents the lowest possible numbers. Chlorine is at position 2.
4. Combine all parts to form the complete IUPAC name of the compound: 2-Chlorospiro[4.5]decane where 'decane' represents the total number of carbons in both rings.

Thus, the correct IUPAC name is 2-Chlorospiro[4.5]decane.