When the PCI EXPRESS was not made, the PCI used to be the best type of slot for the video card on the modem motherboard. However, with the arrival of PCIe or the peripheral component interconnect express, we got an interface standard that could be used for connecting the components with very high speed. And each of the PC motherboards comes with numerous PCIe slots which once can make use of for adding the GPUs like video cards, RAID cards, graphics cards, SSD add on cards, and the Wi-Fi Cards. Thus the correct option above is certainly, 2. PCIe.
