A: Sorry Sir, the Asus X542UN 8th Gen Core i5 With Graphics 15.6" Full HD Laptop does not support Gigabyte 256GB M.2 PCIe SSD, but it only supports M.2 SATA SSD.
A: Yes Sir, the Gigabyte 256GB M.2 PCIe SSD will be able to work well with Asrock B450M Pro4-F motherboard.