Step 1: Comprehending the LEN() function. The LEN() function in MS-Excel serves to enumerate characters within a cell, specifically pertaining to textual data.
Step 2: Evaluating the alternatives. - (A) Financial: The LEN() function does not apply to financial computations. - (B) Logical: The LEN() function is not utilized for logical operations. - (C) Maths & Trig: The LEN() function is not classified as a mathematical or trigonometric function. - (D) Text: This option is correct, as the LEN() function falls under the Text category.
Step 3: Final Determination. The correct classification is (D) Text.