Speed of Gravity?

1. The earth is held in orbit around the sun by gravity.
2. Nothing can travel faster than the speed of light.
3. If the sun instantaneously ceased to exist would the earth:

a. Immediately fly off at a tangent to its orbit.

or

b. Fly off at a tangent approx. 8.5 minutes later.

Comments please!

Oh! and a Happy Christmas to all my readers - ever the optimist!