Solve the following recurrences using the master method: $($a$)$ T $($n$)=2$T $($n$/4)+1($b$)$ T $($n$)=2$T $($n$/4)+($c$)$ T $($n$)=2$T $($n$/4)+$ n $($d$)$ T $($n$)=2$T $($n$/4)+$ n$2$