Each of the following sentences has been divided into five parts (a), (b), (c), (d), and (e). One of these parts may contain a grammatical error. Identify the part that contains the error. If there is no error, choose option (

• E . The spiritual mentor advised (a) / that every individual must cultivate (b) / patience and self-awareness (c) / in order to maintain harmony with themselves and others (d). / No error (e)