What is the minimum number of storage nodes needed to apply N+3 protection to an Isilon cluster so that the cluster stays in read/write mode if three nodes fail?

A.
1

B.
3

C.
5

D.
7

E.
9

Reference: https://docs.google.com/viewer?a=v&q=cache:cTRWIv7DJO0J:www.isilon.com/file-handler-show//520/library-isilon-data-availability-protection.pdf+isilon+minimum+number+of+storage+nodes+needed+to+apply+N%2B3+protection +to+an+Isilon+cluster&hl=en&gl=pk&pid=bl&srcid=ADGEESiT8DfuNDdRfdJ5pdTp2LquIgHAs_jZk Z8sk-klCv5aIJYZlXqy8MhIZuTAqhmmPiMObU8g7Ga8Ot6iZ2FpTcARzEAg1BpgHTA1iWyWYG1vS-AZLzXGk12vk5-Tx19ItYtrN8ks&sig=AHIEtbRtnJ_deRP2CKeO1GiMQ43tp5L7Iw (page 5, third paragraph)