Step 1: Concept Identification: The objective is to determine which listed tests are subtests of the Wechsler Adult Intelligence Scale (WAIS). The WAIS has undergone revisions, but many fundamental subtests remain consistently recognized.
Step 2: Subtest Analysis:
A. Arithmetic: A standard WAIS subtest, historically part of the Verbal Scale (and later, Working Memory Index), measuring numerical reasoning and concentration.
B. Digit Symbol-Coding: A fundamental WAIS subtest, from the Performance Scale (and later, Processing Speed Index), requiring symbol-to-number matching based on a key.
C. Similarities: A core subtest of the Verbal Scale (and later, Verbal Comprehension Index), evaluating abstract verbal reasoning.
D. Object Assembly: Featured in earlier WAIS Performance Scales (e.g., WAIS-R, WAIS-III), involving puzzle assembly. Though omitted in WAIS-IV, it is a historically recognized WAIS subtest.
All four options have been integral to the WAIS at various points, thus all are considered valid.
Step 3: Conclusion:
Arithmetic, Digit Symbol-Coding, Similarities, and Object Assembly are all recognized subtests of the Wechsler Adult Intelligence Scale. Consequently, options A, B, C, and D are all correct.