Choose the best answer to each of the following questions:

a. Which of the following is not a method for ensuring cache coherence in a multiprocessor system?

(1) Write-update snoopy cache,

(2) Write-through cache,

(3) Write-invalidate snoopy cache,

(4) Full map directory protocol.

b. In a 16-node system, which of these networks would have the smallest communication diameter?

(1) N-cube,

(2) Two-dimensional nearest-neighbor mesh,

(3) Ring,

(4) Torus.

c. Which of the following is a rearrangeable network?

(1) Illiac network,

(2) Multistage cube network,

(3) Crossbar switch,

(4) Benes network,

(5) None of the above.

d. In a 64-node system, which of the following would have the smallest node connection degree?

(1) Ring,

(2) Two-dimensional nearest-neighbor mesh,

(3) Illiac network,

(4) N-cube.