Explanation
answer: C. POL_14
Short Explanation with reference:
The Citrix ADC appliance evaluates the rewrite policies in the order of their priority, from lowest to highest.
The priority is a numerical value that indicates the relative importance of the policy. The lower the priority, the higher the importance. The gotoPriorityExpression is an expression that specifies the next policy to evaluate after the current policy is hit. The expression can be either a priority value or the keyword END, which indicates that no further policies are evaluated. Therefore, in this scenario, the policy evaluation order is as follows:
POL_12 is hit first, as it has the lowest priority (90). It has a gotoPriorityExpression of NEXT, which means that the next policy in priority order is evaluated.
POL_15 is evaluated next, as it has the next lowest priority (100). It has a gotoPriorityExpression of END, which means that no further policies are evaluated.
POL_13 and POL_14 are not evaluated, as they have higher priorities (101 and 120) than POL_15, and POL_15 has a gotoPriorityExpression of END.
Therefore, the correct answer is C. POL_14, as it is the policy that is evaluated last, considering POL_12 is hit first.
Configuring rewrite policies | NetScaler : Policy binding and evaluation | NetScaler 14.1

Explanation
answer: C. Configure HA fail-safe mode on each Citrix ADC independently.
Short Explanation with reference:
HA fail-safe mode is a feature that allows the Citrix ADC appliance to continue processing traffic even if both nodes in an HA pair become unavailable or fail a health check. This prevents the appliance from dropping existing connections or rejecting new requests, and ensures that the business websites are always available.
HA fail-safe mode can be enabled or disabled on each node independently by using the -failSafe option in the CLI or by checking or unchecking the Fail-Safe Mode check-box in the GUI. Therefore, the correct answer is C: Configure HA fail-safe mode on each Citrix ADC independently.
Configuring high availability fail-safe mode | NetScaler