Comprehensive and Detailed Explanation From Exact Extract of DevOps Engineer documents only:

The requirement is to shift traffic automatically in equal increments over a defined total deployment time with no manual intervention. In AWS CodeDeploy blue/green deployments for Amazon ECS, the TimeBasedLinear traffic routing option is specifically designed for this purpose.

Option A is correct because:

TimeBasedLinear shifts traffic in equal percentages.

The deployment proceeds automatically at each interval.

linearPercentage defines how much traffic is shifted each time.

linearInterval defines how often the traffic shift happens.

This supports gradual traffic shifting and zero-downtime blue/green deployment behavior.

Why the other options are incorrect:

B. AllAtOnce shifts all traffic immediately, not in equal increments over time.

C. TimeBasedCanary shifts traffic in an initial portion and then the remainder later. That is not equal incremental shifting across the full deployment period.

D. This option is too generic and does not specifically identify the CodeDeploy configuration that provides equal incremental automatic traffic shifting. The exact feature required is TimeBasedLinear.