I am between B and D.

IMO B. More Industrilized -> Increase N of Carcinogens

Conclusion - Incidence of cancer increasing faster in the industrilized country.

A. It supports the conculsion and explain why it is increasing faster
B. If there is a threshold to carcinogens before cancer can occur, it means that cancer may not occur or increase until an industrilized country meets the threshold. Two things to consider in this choice. "Some" and "Sufficiently high". "Some" also includes "all" so we are also talking about all cancer. And "sufficiently high" raises the bar high for the theshold.
C. Support the cause/effect relationship.
D. Support the cause/effect relationship.
E. Support the conclusion

@vishalj

none of those are the OA

IMO E is the answer.

A says that since carcinogens increased, area affected increases. So this will cause cancer. Support
B Cancer will not occur unless carcinogens level is high. Now level is high, cancer will occur.
C Competitiors are also producing carcinogens. Carcinogens are more, cancer will occur.
D country is more industrialized so potent carcinogens will produce and this will cause cancer.

E What to do whether increase is related with % or with number.

What's the OA?

reply2spg wrote:IMO E is the answer.

A says that since carcinogens increased, area affected increases. So this will cause cancer. Support
B Cancer will not occur unless carcinogens level is high. Now level is high, cancer will occur.
C Competitiors are also producing carcinogens. Carcinogens are more, cancer will occur.
D country is more industrialized so potent carcinogens will produce and this will cause cancer.

E What to do whether increase is related with % or with number.

What's the OA?

Yes, E is the answer.