The correct options are
B Rishabh, a civil engineer.
D Suresh, an architect.
Civil engineering involves building infrastructure whereas architecture deal with building design. Thus, both are forms of skilled labour, and both Rishabh and Suresh must have earned a degree in their related fields. Ali is considered unskilled because he doesn't have the relevant education or experience. Amish is also a skilled worker, but his experience and education are not directly related to the task at hand. Hence, Rishabh and Suresh would be the best options for Rajesh.