The correct answer is A) volunteering time.
Danielle has decided to work with an organization that helps soldiers deployed overseas. The opportunity she chooses is writing letters back and forth to soldiers.
The type of charitable donation Danielle is making to the soldier’s organization is "volunteering time."
Money is not a limitation when you want to help someone or an organization. If you do not have enough money to send and support a good cause, you always have your time. You can volunteer time as Danielle does to support a good cause. This is a good and valid way to help people who need you.