Here are the answers based on the primary stress patterns of the words:

1. C. inflate (The stress is on the second syllable: in-FLATE, while the others have stress on the second syllable: con-FIDE, com-FORT, se-VERE.)

2. A. biology (The stress is on the second syllable: bi-OL-o-gy, while the others have stress on the third syllable: en-VIRON-ment, ge-O-gra-phy, pres-TI-gious.)

3. C. proportion (The stress is on the second syllable: pro-POR-tion, while the others have stress on the first syllable: es-TI-mate, trans-FORM-a-tion, ur-BAN-ization.)

4. D. population (The stress is on the third syllable: pop-u-LA-tion, while the others have stress on the second syllable: ag-RI-cultural, un-EM-ployed, sus-TAIN-able.)

5. C. revolution (The stress is on the last syllable: rev-o-LU-tion, while the others have stress on the second syllable: ur-BAN-ization, eco-NO-mic, sus-TAIN-able.)

So the marked answers are:
1. C
2. A
3. C
4. D
5. C