Mary worked in customer service for 40 years. She was known to be insightful and able to overcome obstacles that she encountered on a daily basis. She retired from her management position at the age of 65. Now, as a volunteer at a polling bureau, she puts her ability to use common sense and good judgment in making decisions to good use. Which ability, common to many older people but not all, is Mary displaying?
a. intelligence
b. expertise
c. wisdom
d. grace