The sentence in which the subject and verb agree is:
B. Without help from anyone, Jackson mows the front yard once a week.
In this sentence, "Jackson" (singular subject) agrees with "mows" (singular verb).
The other sentences contain subject-verb agreement errors:
- A: "Marco and his entire family loves" should be "love" because the subject is plural.
- C: "Melissa and her sisters helps" should be "help" because the subject is plural.
- D: "everyone except for Andre want" should be "wants" because "everyone" is treated as singular.