The IUPAC names for the given compounds are determined by identifying the longest carbon chain and then numbering the substituents to give the lowest possible locants.

For compound (i), the longest chain is pentane with four methyl groups at positions 2, 2, 4, and 4, making it 2, 2, 4, 4-Tetramethylpentane. For compound (ii), the longest chain is pentane with two methyl groups at position 3, giving the name 3, 3-Dimethylpentane.

For compound (iii), tetra – tert-butylmethane, the correct IUPAC name is 3,3-Di-tert-butyl -2, 2, 4, 4-tetramethylpentane.