Explanation:

ALU is the standard acronym for 'Arithmetic Logic Unit'. Option (a) 'Arithmetic logic unit' is a digital circuit within the CPU that performs arithmetic operations (like addition, subtraction) and logical operations (like comparisons). Options (b) 'Arithmetic large unit' and (c) 'Arithmetic long unit' are incorrect expansions of the acronym. Option (d) 'All' is incorrect as only (a) is correct. Option (e) 'None of these' is incorrect because (a) is the correct expansion.