CAUTION----All the letters except 'A' are present in the main word. Hence, 'CAUTION' cannot be formed the letters of the given word 'CONSTRUCTION' .

All the letters except second 'L' are present in the main word.
Hence, 'INSTALLATION' cannot formed from the letters of the given word 'NATIONALISATION' .

MASTER---All the letters of this word are present in the main word. Hence, 'MASTER' can be formed from the letters of the given word 'MEASUREMENT' .

MENTION----All the letters of this word are present in the main word.
Hence, 'MENTION' can be formed from the letters of the given word 'COMPENSATION' .

Since, 1st, 4th, 7th and 11th letters are I, E, R and T , respectively.
Hence, two meaningful words RITE can be formed.

The word 'BRAIN' cannot be formed from 'REASONABLE' due to absence of letter i.

UNISON cannot be formed letter 'S' is not in the given word.

The word which cannot be formed form 'Specification' is 'Fainting' due to absence of the letter '(G)' and only one 'N' is present in the given word.

Using the letters of the given word, the word LIZARD cannot be made because D is not there in the given word.

From the word 'CONCEPTUALISATION' ,The word, which cannot be formed is STATUS as it contains only one 'S'.