Recall the IUPAC priority order of principal functional groups

For naming organic compounds, the relevant decreasing order of priority among the listed groups is:

$- ext{COOH} > - ext{SO}_3 ext{H} > - ext{COOR} > - ext{COCl} > - ext{CONH}_2 > - ext{CN} > - ext{CHO}$

More specifically for the groups appearing in the options:

$- ext{COOH} > - ext{SO}_3 ext{H} > - ext{COOR} > - ext{COCl} > - ext{CONH}_2 > - ext{CN} > - ext{CHO}$

Check option A

Option A says: $- ext{COOH} > - ext{CONH}_2 > - ext{COCl} > - ext{CHO}$

But acid chloride has higher priority than amide: $- ext{COCl} > - ext{CONH}_2$

So A is incorrect.

Check option B

Option B says: $- ext{SO}_3 ext{H} > - ext{COCl} > - ext{CONH}_2 > - ext{CN}$

This matches the standard priority order: $- ext{SO}_3 ext{H} > - ext{COCl} > - ext{CONH}_2 > - ext{CN}$

So B is correct.

Check option D

Option D says: $- ext{COOH} > - ext{COOR} > - ext{CONH}_2 > - ext{COCl}$

But acid chloride has higher priority than amide: $- ext{COCl} > - ext{CONH}_2$

Therefore D is incorrect.

Conclusion

The correct decreasing order given in the options is: oxed{- ext{SO}_3 ext{H} > - ext{COCl} > - ext{CONH}_2 > - ext{CN}}

Hence, the correct option is B.