In sentence (1), "He seized opportunity offered to him," the error is missing the article "the" before "opportunity." The correct sentence should be "He seized the opportunity offered to him."

In sentence (2), "Sham went out to play Mohan stayed at home to work," the error is the lack of punctuation and clarity. It should be separated into two sentences or clauses for clarity: "Sham went out to play. Mohan stayed at home to work."

In sentence (3), "Some children are not able to distinguish good and evil," there is no grammatical error. However, it might be considered incomplete without further context to clarify what the sentence refers to.

Sentence (4), "The book is interesting, informative and easy to read," is grammatically correct and well-structured, making it the one with no error.