You are referencing and using arrays of a CDT (Custom Data Type). Which two statements are true? (Choose two.)

You are referencing and using arrays of a CDT (Custom Data Type). Which two statements are true? (Choose two.)

A. Other Appian functions can be used within the square brackets "[]" when using dot notation to return specific data from the array.

B. There is no difference between using "dot notation" and the index() function.

C. An array of integers can be passed as the second parameter to the index() function to return the data at those position in the array.

D. The function where contains can act on operands of different types.

I think options B and C are correct. Option D is incorrect. However, option A is not clear to me.

The following code does not give any error:

Hence, is option A correct? If that is the case, which one is incorrect?