Question

You should to read the newspapers regularly if you want to be well-informed.

• A. Ought to
  
• B. Have to
• C. Should be
• D. NO IMPROVEMENT

Answer 1

Answer: (A)

Ought to

Modal verbs are helping verbs that express the mood of a sentence, like permission(may), obligation (must), possibility (can), etc.
The underlined word 'should' in "should to" refers to an obligation or duty. It isn't followed by 'to'. It is directly followed by the verb, hence this part must be changed. So, option D is incorrect.
Option A: 'Ought' is also a modal that refers to obligation. The difference between 'should' and 'ought' is that the latter has to be followed by a to-infinitive.
Option B: 'Have to' also refers to obligation, but there is a difference in meaning between 'have' and 'ought'.
The former (have to) is used when there is no other choice in that situation. For example, You have to drive on the left side of the road.
The latter (ought to) is used as a form of advice, there isn't a hard and fast rule.
Since the sentence is an advice or a recommendation, option A is correct and B is incorrect.
Option C: 'Should be' is used when the sentence is in continuous tense. Then the verb form is a present participle (reading): 'should be reading'. It isn't the situation here, hence C is also incorrect.