Answer:
She should send a Mail or a Message.
Explanation:
Since the article used in the sentence is "A" and not "An", it would not be correct to include the "Email" option because you would be making a grammatical error .
But, it is correct to say that you can send a mail or a message since in addition to being correct in the sentence they are also equally valid communication systems.
A large percentage of people use mobile phones, so it is correct to say that they have the option of receiving messages.
