Step 1: Understanding the Question
The question asks to identify the library classification system that uses a "mixed notation." Notation is the system of symbols (numbers, letters, etc.) used to represent the classes in a classification scheme. A mixed notation uses more than one type of symbol.
Step 2: Key Formula or Approach
The approach is to analyze the notational system of each classification scheme listed.
Pure Notation: Uses only one type of symbol (e.g., only numbers or only letters).
Mixed Notation: Uses a combination of symbols (e.g., letters and numbers).
Step 3: Detailed Explanation
(A) DDC: Uses a pure notation of Arabic numerals (e.g., 510 for Mathematics).
(B) UDC: Uses a mixed notation of numerals and various punctuation marks (e.g., +, /, :), but its base is numeric.
(C) CC: Uses a highly mixed notation of letters (uppercase and lowercase), numbers, and punctuation symbols.
(D) LCC: Uses a mixed notation consisting of one or two uppercase letters followed by Arabic numerals (e.g., QA for Mathematics, Z for Library Science). This is a classic example of a mixed notation.
While both UDC and CC use mixed notations, LCC is the most prominent example that primarily mixes letters and numbers in its top-level classes. The question asks which scheme uses it as its basis. The basis of LCC is letters for main classes and numbers for subdivisions.
Step 4: Final Answer
The Library of Congress Classification (LCC) is fundamentally based on a mixed notation of letters and numbers. Therefore, Option (D) is the correct answer.