$(13)$ Which item below was a $3$G dedicated connection switching technology that organized digital data into $53-$byte $$cells$$ and transmitted these cells over a physical medium using digital signal technology, typically SONET $?$

$($a$)$ ATM

$($b$)$ PGW

$($c$)$ UTRAN

$($d$)$ Metro Ethernet

$($e$)$ Free Space Optics $($FSO$)$