which router will be the OSPF designated router?

Refer to the Exhibit.

Referring to the exhibit, R1, R2, and R3 boot at the same time. Several minutes later, R4 boots.
After R4 has been online for 40 seconds, which router will be the OSPF designated router?

A.
R1

B.
R2

C.
R3

D.
R4

Explanation: