The correct option is
D Model D
To find the grid model representing the final value as 0.54, we need to observe the value represented by each model.
Calculating Model A, we get:

So, 0.6
× 0.8 = 0.48
∴ Model A represents the value 0.48.

Calculating Model B, we get:

So, 0.4
× 0.5 = 0.20
∴ Model B represents the value 0.20.

Calculating Model C, we get:

So, 0.6
× 0.5 = 0.30
∴ Model C represents the value 0.30.

Finally, calculating Model D, we get:

So, 0.6
× 0.9 = 0.54
∴ Model D represents the value 0.54.

Hence, the only model that represents the final value 0.54 is Model D.