Regarding Blocks in OutSystems reactive apps, which of the following options is correct?

Regarding Blocks in OutSystems reactive apps, which of the following options is correct?
A . Blocks can only be instantiated on Screens.
B. Blocks can be instantiated on Screens and other Blocks.
C. Blocks can be instantiated on Client Actions on the Screen.
D. Blocks can be instantiated on Screens and external HTML pages, using a special HTML tag.

Answer: B