Target Corporation provides the following footnote relating to its retirement plans in its 2017 10-K report:

Defined Contribution Plans:

Team members who meet eligibility requirements can participate in a defined contribution 401(k) plan by investing up to 80 percent of their eligible earnings. as limited by statute or regulation. We match 100 percent of each team member's contribution up to 5 percent of eligible earnings. Company match contributions are made to funds designated by the participant, none of which are based on Target common stock. Benefits expense related to these matching contributions was $219 million, $197 million, and $224 million in 2017, 2016, and 2015, respectively.

a. Does Target have a defined contribution or defined benefit pension plan? Explain.

b. How would Target account for its contributions to its retirement plan?

c. How is Target's obligation to its retirement plan reported on its balance sheet?

d. Do you see any problems for employees in Target's plan?