"Quitting your job to find another" is the answer for the given question.
Step-by-step explanation:
I guess certain options since the options are not provided by you.
A. Requesting a promotion : This is one of the right method. An employee can always talk with the manager explaining about his achievement and asking for promotion.
B. Requesting a merit increase in pay : Yes, this is once again possible, because an employee is the right person to speak about himself and the contribution towards the company and makes his salary equivalent to the contribution.
C. Quitting your job to find another : This should not be done, because here the motto is to increase the money, and if the person quits the job, there is no guarantee that he gets the job immediately.
D. Looking for a better job without quitting your old job: Yes this is recommendable because the organization always take people who are running in the market.