In TypeScript, the error Element implicitly has an 'any' type because index expression is not of type 'number' typically occurs when:
A. Accessing an array element using an index that is not explicitly typed as a number.
B. Using a string as an index to access an element in an object without proper type annotation.
C. Declaring a variable without specifying its type in a loop iteration.
D. Attempting to access a property in an object without using a type assertion.