One of the following statements contains a word used incorrectly or inappropriately. Choose the option which has the incorrect or inappropriate usage of the word.

Question and options

1. They found that all the flowers placed on their mother's grave had withered within a week.
2. The pet dog could not come to terms with his master's death and went to grave for him, even refusing to eat for several days.
3. When the witness was summoned by the lawyer, he made grave allegations against the accused.
4. The landlord issued a warning to the tenants that non-payment of rent was a grave matter and would lead to a court case.