What Differentiates Flexible Spending Accounts (FSAs) and Health Savings Accounts

Multiple Choice

What differentiates Flexible Spending Accounts (FSAs) and Health Savings Accounts (HSAs) ?

A) HSAs expire on an annual basis but FSAs continue perpetually.
B) FSAs expire annually but HSAs may be reserved for use late in life.
C) Amounts contributed to FSAs may not be rolled over from one year to the next.
D) Only HSAs may be deducted from employee on a pre-tax basis.