You need to meet the technical requirements for Server3.

Installing and authorizing a DHCP server in an Active Directory-integrated environment requires two distinct sets of rights: local Administrators group membership on Server3 to install the DHCP Server role itself, and Enterprise Admins group membership to authorize that server in AD DS, because DHCP server authorization is stored as a forest-wide object under CN=NetServices,CN=Services,CN=Configuration and only Enterprise Admins can create or modify objects there by default. Admin1 is a member of Contoso\Enterprise Admins, which grants exactly this forest-wide right and also carries local administrative rights on every domain-joined computer in the forest, including Server3, so Admin1 can both install the role and authorize the server, fully satisfying the requirement on his own. Admin2, a member of only Contoso\Domain Admins, has full administrative rights over contoso.com and its member computers, but Domain Admins does not carry the right to authorize a DHCP server in the forest-wide NetServices container, so Admin2 cannot complete authorization even though he can install the role. Admin3, a member of Canada\Domain Admins, has administrative rights limited to the canada.contoso.com domain and likewise lacks the Enterprise Admins-only authorization right needed here, since Server3 and the DHCP authorization object both fall outside that domain ' s scope of control. Because only Admin1 holds both the local administrative rights needed to install the DHCP Server role on Server3 and the Enterprise Admins membership needed to authorize it in AD DS, Admin1 only is correct.