Static type checking is an important tool in the early detection of programming bugs. If the type of a given expression does not match the expected type of the place where the expression is being used, this in most cases indicates that there is a bug in that program. Select all the true statements about Python and JavaScript type checking:

a. React and Vue frontend components can make use of TypeScript in order to enable static type checking

b. Any JavaScript program is also a TypeScript program since TypeScript is a language extension of JavaScript

c. Type hints in Python can be added "gradually", so one can leverage both dynamic and static typing

d. When using Python type hints on a Django backend API, one must then also use TypeScript for the frontend component e. Type annotations that cause static type checking errors will lead to the program crashing when executinG