Answer:
All the options given here are correct because they are the same.
Marking up the text during reading is necessary for critical thought and helps readers make connections to what they read.
Step-by-step explanation:
The subject-verb agreement simply means that the subject of a sentence and the corresponding verb must be in agreement in number.
The sentence would have been incorrect if it was written as follows:
Marking up the text during reading is necessary for critical thought and help readers makes connections to what they read.
The underlined phrase above is the subject and it holds the plural form of the word text. The rules state that singular subjects must be aligned with singular verbs. While plural subjects must be aligned with the plural verbs.
Therefore, the correct words are helps and make.
Cheers