This file should be an Excel file (.xlsx) with the following structure:

Column A: question_text
Column B: question_type
Column C: options
Column D: correct_answer
Column E: marks

Row 1: Headers as above
Row 2: "What is the capital of France?", "multiple_choice", "London|Paris|Berlin|Madrid", "Paris", 1
Row 3: "The Pacific Ocean is the largest ocean on Earth.", "true_false", "True|False", "True", 1
Row 4: "What is the chemical symbol for gold?", "short_answer", "", "Au", 2
Row 5: "Explain the water cycle and its importance to Earth's ecosystem.", "essay", "", "", 5

Note: This is a text representation. An actual binary .xlsx file would need to be created using PHP libraries such as PhpSpreadsheet.