A ∆-∆ connected transformer is connected to V-V connected transformer. The ratio of VA rating of the V-V connected transformer and ∆-∆ connected transformer is:

Correct option is B

​$$\text{To determine the ratio of the VA rating of a V - V connected transformer to a } \Delta - \Delta \text{ connected transformer, we can use the relationship between the two configurations.}\\\text{In a } \Delta - (\text{Delta-Delta}) \text{ connection, all three phases are used, and the power transfer is maximized.}\\\text{However, in a V - V (or Open-Delta) connection, only two transformers are used instead of three, which results in a reduced power capacity. The VA rating of the V - V connection is 57.7\% (or } \frac{1}{\sqrt{3}} \text{) of the VA rating of the } \Delta - \Delta \text{ connection.}\\\text{Therefore, the ratio of the VA rating of the V - V connected transformer to the } \Delta - \Delta\text{ connected transformer is:}\\\frac{V_{A-V-V}}{V_{A-\Delta-\Delta}} = 0.577$$​​