Typically, it will look like: DSL-2750U_C1_v1.0.16_11232016.bin (dates and version numbers vary).
D-Link provides region-specific firmware. It is highly recommended to use the official or your local D-Link support site for the most stable versions. Index of /pub/ADSL/DSL-2750U/Firmware/Rev.C/1.0.14 dlink dsl2750u c1 firmware install