The correct answer is: B. addicted to
The preposition “to” is used to express addiction to something. For example, “He is addicted to drugs” or “She is addicted to gambling.”
The preposition “of” is used to express possession or ownership. For example, “The house is made of wood” or “The book is full of interesting stories.”
The preposition “for” is used to express a purpose or goal. For example, “I am going to the store for milk” or “I am saving money for a new car.”
The preposition “with” is used to express a means or instrument. For example, “I cut the bread with a knife” or “I painted the house with a brush.”
In the sentence “Her son is addicted to alcohol,” the preposition “to” is used to express the fact that the son has a strong and uncontrollable desire to drink alcohol.