Final answer:
The correct arrangement of numbers to form a meaningful word is 354621, which forms the word 'EMAILS'.
Step-by-step explanation:
Looking at the given options, we need to arrange the numbers 1, 2, 3, 4, 5, and 6 in a way that forms a meaningful word. Evaluating each option:
- a. 321654: This arrangement does not form a meaningful word.
- b. 623451: This arrangement does not form a meaningful word.
- c. 354621: This arrangement forms the word 'EMAILS'.
- d. 523641: This arrangement does not form a meaningful word.
Therefore, the correct option is c. 354621, as it forms the word 'EMAILS'.