Select the most appropriate adjective to fill in the blank. His Ph.D.…

Concept

When one member is compared with an entire group, English uses the superlative degree, normally with the definite article “the”. Some adjectives are irregular: bad changes to worse in the comparative and worst in the superlative.

Application

The phrase “of all the exam scores” compares one score with the whole set of scores. The blank therefore requires the superlative form of bad: worst.

Contrast

• “Baddest” is not the standard superlative form of bad.

• “Badder” is not the standard comparative form; moreover, a comparative would compare two items rather than one item with the whole group.

• “Bad” is the positive form and does not express comparison with the group.

Cross-check

The completed sentence reads naturally as “His Ph.D. entrance-exam score is the worst of all the exam scores he has received so far.” The irregular sequence bad–worse–worst confirms the result.

Result: worst