Here are the answers for each set based on their main stress patterns:

1. **A. ancient** - Stress on the first syllable.
**B. barefoot** - Stress on the first syllable.
**C. basic** - Stress on the first syllable.
**D. communal** - Stress on the second syllable. **(Different)**

2. **A. castle** - Stress on the first syllable.
**B. anniversary** - Stress on the third syllable. **(Different)**
**C. complex** - Stress on the first syllable.
**D. monument** - Stress on the first syllable.

3. **A. illiterate** - Stress on the second syllable.
**B. loudspeaker** - Stress on the first syllable.
**C. observe** - Stress on the second syllable.
**D. occupy** - Stress on the second syllable. **(Different)**

4. **A. promote** - Stress on the second syllable.
**B. recognise** - Stress on the first syllable. **(Different)**
**C. religious** - Stress on the second syllable.
**D. behave** - Stress on the second syllable.

So, the words with different stress patterns are:
1. D. communal
2. B. anniversary
3. D. occupy
4. B. recognise