The following sentence has been divided into parts. One of them may contain an error.
Stella usually manages / the waste materials and / disposed them meticulously.

Correct option is B

The error is in the verb tense "disposed" in part (b).
The sentence starts with "Stella usually manages," which is in the present tense.
To maintain consistency in verb tenses, the verb "disposed" should be in the present tense as well, which would be "disposes."
The correct sentence should be "Stella usually manages the waste materials and disposes them meticulously."
Grammatical rule used:
· Tense consistency: When two actions are connected by a conjunction (such as "and") and describe habitual actions, the verbs should be in the same tense. Since "manages" is in the present tense, "disposes" should also be in the present tense.
Example:
· Incorrect: He washes the dishes and put them away.
· Correct: He washes the dishes and puts them away.