Here are the words grouped by their stress patterns:

1. construction (con-STRUC-tion)
2. electrician (elec-TRI-cian)
3. accomplish (ac-COM-plish)
4. anxiety (an-XI-e-ty)

**Different stress:**
The word “liveable” (in option B) has primary stress on the first syllable (LIVE-able), while the other words tend to have the stress on later syllables.

5.
1. facility (fa-CIL-i-ty)
2. assignment (as-SIGN-ment)
3. environment (en-VI-ron-ment)
4. additional (ad-DI-tional)

**Different stress:**
“Assignment” has the stress on the second syllable (as-SIGN-ment), while the others usually place stress in different areas.

6.
1. collector (col-LECT-or)
2. additional (ad-DI-tional)
3. attention (at-TEN-tion)
4. optimistic (op-TIM-is-tic)

**Different stress:**
“Collector” has stress on the second syllable (col-LECT-or), while the others typically stress the next syllable.

Final determination, **the answer varies contextually** based on how you analyze the stress patterns, but "liveable" and "collector" clearly stand out. In terms of stress, always check which part of the word is emphasized when pronouncing.