Hi

First of all, the redundancy in one line does not contradict the redundancy in the subsequent line because you overlooked a small detail

redundancy results in decreased precision

of space available in any information system is limited

Per see redundancy helps us to decrease mistakes it is another form of information or instructions to add.

Now, A is clearly off

(A) Their findings provocatively challenge the standard explanation of redundancy in genes.

No at all. They use the concept of redundancy and of the limited space of information to tell us that a TRADE-OFF exists.

between two conflicting priorities: precision and the avoidance of gross mistakes.

The rational of the trade-off is used in a system and how the genes work alike

I hope now is more clear