I am using a Dell Vostro and the screen size is very small which is why I am getting a 4K monitor. At the moment, I have a standard Dell monitor connected via the HDMI port which works fine.

Need to use a dual monitor setup..
Now, would I be able to use two monitors simultaneously - one with the existing setup HDMI to HDMI connection and the other with the new 4k monitor  60 HZ  3840 * 2160 via the USB C port at the same time? Is that supported?
If yes, should we use a USB-C to display port or USB-C to HDMI for this purpose??