D. SATA stands for Serial Advanced Technology Attachment, its main application is to connect the host with the hard disk driver (HDD) or the solid state disk (SSD), The SATA environment is a point-to-point connection scheme (half-duplex). SATA uses 8b/10b encoding for clock recovery and DC balance and can transmit and recieve up to 6 Gb/sec differnetial NRZ serial stream. SATA standards do not define switches or other hardware mechanisms that allow the architecture to go beyond a single device to host connection. To overcome this restriction, the SATA community has defined a hardware and software scheme that will allow more than one (or two for ATA emulation) device to be attached to a host system. This is accomplished through a mechanism known as a Port Multiplier [9].  
E. SAS