The FRCP allows each party up to 10 depositions :

a. To be taken however the party sees fit.

b. To be computed discretely allowing for the fact that a witness's deposition may be taken more than once. 

c. To be calculated cumulatively for plaintiffs, defendants, and third-party defendants.

d. As long as they are taken in a one-year time span.

e. None of the above.