Triumba birds reside in the polar regions and need to migrat

[BTGmoderatorAT]

Triumba birds reside in the polar regions and need to migrate to warmer areas in winters since winters in the polar regions are not conducive to the survival of the birds. In recent years, because of some unanticipated genetic changes, the flying capability of the birds has been declining and is expected to continue do so in the future.

Which of the following statements is best supported by the passage above?

A)At least one species that resides in the polar regions cannot survive in the summer by migrating to other regions.
B)If Triumba birds don't develop measures to counter adversarial genetic changes, they face a likelihood of extinction.
C)Over the past few years, some of the Triumba birds would not have flown back to the polar regions because of limited flying ability.
D)Unless Triumba birds develop an ability to live in the polar regions during winter, they will be extinct in some time.
E) The flying capability of Triumba birds is worse than that of other polar region birds that do not migrate to warmer areas in the winter.

OA: B

What's wrong with options A and C?

[VJesus12]

Hello ardz24.

I also would like to know what is wrong with A and C ? I can't see the mistake.

Experts, may you help us here?