Which word has the following phonemes: 'th, u, mb'?

The phonemes 'th, u, mb' can be broken down as follows: 'th' represents the voiced sound found at the beginning of the word, 'u' represents the short vowel sound, and 'mb' represents the consonant cluster at the end of the word. The word 'thumb' incorporates all three phonemes in the correct sequence.

In this case, 'th' is pronounced as the voiceless dental fricative, which is the initial sound in 'thumb.' Following this, the short 'u' sound is present, leading to the 'mb' consonant cluster which completes the word.

Other words in the list do not contain all three of the specified phonemes in the correct order. For instance, 'thick' starts with 'th' but lacks the following 'u' phoneme and ends differently. 'Thought' contains 'th' but has a different vowel sound and a different ending, while 'sigh' does not contain 'th' at all and presents a completely different structure. Hence, 'thumb' is the only word that fits the criteria given in the question.