Mark the letter A, B, C, or D to indicate the word that differs from the other three in the position of primary stress A. breakfast B. hometown C. supper D. dinner

The word that differs from the other three in the position of primary stress is B. hometown. In this word, the primary stress falls on the first syllable (HOMEtown), while in the other words, the stress also falls on the first syllable but they are all one-syllable words.