The word MEASUREMENT contains letters M, E, A, S, U, R, N, T, M, E, N, T. 'METER' can be formed using M, E, E, T, E, R from these letters. 'ASSURE' needs two S's but only one is available. 'SUMMIT' needs two M's and two I's but 'I' isn't in MEASUREMENT. 'EARTH' needs 'H' which isn't available.