Let's take the sides one by one and try to find the type of triangle.
A. 3,4,5
The sides are not equal, hence it's a scalene triangle.
Moreover, 32+42=25=52
∴ It's a right triangle too,
Hence, it's a scalene right triangle.
B. 2,3,4
The sides are not equal, hence it's a scalene triangle.
Moreover, 22+32=13≠42
∴ It's not a right triangle.
Hence, it's a scalene triangle.
C. 4,4,5
Two sides are equal, hence it's an isoceles triangle.
Moreover, 42+42=32≠52
∴ It's not a right triangle,
Hence, it's an isosceles triangle.
D. 3,3,3√2
Two sides are equal, hence it's an isosceles triangle.
Moreover, 32+32=18=(3√2)2
∴ It's a right triangle too,
Hence, it's an isosceles right triangle.