Answer:
211.30.194.81
Step-by-step explanation:
IP addresses use 8 bits for each of the four digits in decimal notation, or 2 digits in hexadecimal notation.
Hexadecimal numbers use digits from 0 to 9 and A to F, for decimal numbers in the range from 0 to 15.
To convert from hexadecimal to decimal, we need to know that each digit will have the value:

Where n is the hexadecimal number to convert, and p is the digit position.
For example, for D3:

Splitting the given address (0xD31EC251) in pairs:
1st digit: D3 = 211 decimal
2nd digit: 1E = 30 decimal
3rd digit: C2 = 194 decimal
4th digit: 51 = 81 decimal
Joining all the values using the dotted notation:
211.30.194.81