Directions: The sentence below or part thereof has been underlined. The underlined part may have an error of grammar or diction. Select the option that best corrects the error, if any.

To keep the elephants in good physical condition the keeper trims their tusks with a hacksaw every three years and oils their hides once a year so that their skin won't crack.

To keep the elephants in good physical condition the keeper trims their tusks with a hacksaw every three years and oils their hides once a year so that their skin won't crack.

To keep the elephants in good physical conditions the keeper trims their tusks once in three years with a hacksaw and puts oil on their hides once a year to avoid its cracking.

The keeper trims the tusks once in three years and oils their hides once a year to that the skin won't crack to keep the elephants in good physical condition.

For keeping the elephants in good physical condition the keeper trimmed their tusks once every three years and oiled the hides so that they won't crack.

Trimming of tusks with hacksaw and oiling of hides to avoid them from cracking is done by the keeper to keep elephants in good physical conditions.