Answer:
d. root
Step-by-step explanation:
phpMyAdmin is a web application used to administer and manage MySQL database instances. It can also be used for querying a table/tables in the database using SQL. phpMyAdmin comes pre-configured with a default user 'root' with no password. From a security standpoint, a password can be assigned for root user after first login. Other userids can also be created for effective database administration.