a client has a job as a tenured professor of finance at a successful university. tenure implies that the professor can only lose the job in extreme cases of misconduct or closing of the program. in addition, this professor is in good health, has a healthy spouse, both of whom have life expectancies into their 90s, and expects to work another 15 years, but can work longer if retirement needs require it. the salary, although sufficient for a comfortable lifestyle, will not make the couple wealthy, in and of itself. what kind of investment portfolio is appropriate for this client?