B. 8.1
C. 11.3
D. 12.3
If you get this right I will mark you as a brainliest

Use pythagoras theorem that is 4.6^2 + 10.3^2 = x^2.
21.16 + 106.09 = 127.25
Hence, x^2 = 127.25
x= 11.28 => 11.3 that is option C