To arrange the given words in alphabetical order, we need to compare the first letter of each word.

1. Agriculture
2. Accurate
3. Assignment
4. Attention

Comparing the first letters, we find that "Agriculture" starts with 'A', "Accurate" also starts with 'A', "Assignment" starts with 'A', and "Attention" starts with 'A' as well.

Since all the words begin with the same letter, we need to move on to the second letter.

1. Agriculture
2. Accurate
3. Assignment
4. Attention

Comparing the second letters, we find that "Agriculture" has 'g' as the second letter, "Accurate" has 'c', "Assignment" has 's', and "Attention" has 't'.

Based on the comparison, "Assignment" comes before "Attention" because 's' comes before 't' in the alphabetical order.

1. Agriculture
2. Accurate
3. Assignment
4. Attention

Now, comparing the third letters, we find that "Agriculture" has 'r' as the third letter, "Accurate" has 'c', "Assignment" has 's', and "Attention" has 't'.

Based on the comparison, "Accurate" comes before "Assignment" because 'c' comes before 's' in the alphabetical order.

1. Agriculture
2. Accurate
3. Assignment
4. Attention

Finally, comparing the fourth letters, we find that "Agriculture" has 'i', "Accurate" has 'u', "Assignment" has 's', and "Attention" has 't'.

Based on the comparison, "Accurate" comes before "Agriculture" because 'u' comes before 'i' in the alphabetical order.

1. Accurate
2. Agriculture
3. Assignment
4. Attention

Therefore, the word that comes last in alphabetical order is "Attention" (Option D).