Institution: Directorate of Primary Education - DPE Exam: Primary Exam Question Solution 24-05-2019
Topic: Preposition, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

The phrase "She was blessed … a son" requires a preposition that appropriately conveys the relationship between the subject ("She") and the noun ("a son"). Among the provided options, "with" is the most fitting choice.

Using "with," as in "She was blessed with a son," indicates that having a son is considered a positive fortune or gift that has been bestowed upon her. This usage reflects a common expression in English where "blessed with" suggests receiving something good or fortunate.

The other options don't align as well with the intended meaning. "By" would imply that the blessing came from a particular source, which wouldn’t fit the context of the sentence. "For" suggests a purpose or reason, which isn’t applicable here. "In" typically denotes a state or condition and doesn’t convey the idea of receiving a positive addition to one’s life.

Thus, "with" captures the sentiment of receiving a valued blessing, making it the correct choice in this context.