B seems to be a more accurate answer because An SNMP trap storm is defined as four or more identical traps occurring within a 30-second period. Option C doesn't say 3 or more identical traps. It just mentions 3 or more traps

Because if it is the correct one, it is B. Do they change it?

My answer is B - Four or more identical SNMP traps that have been logged in within the past 30 seconds, which is found in the Study Guide Pg249

See book: An SNMP trap storm is defined as four or more identical traps occurring within a 30-second period. To be considered identical, an SNMP trap must meet three criteria: Is from the same device—A device that has the same IPv4 address Has the same trap identifier—The same MIB trap Object ID (OID) Has the same number of variable string values—In the same order and with the same values

Definition: An SNMP trap storm is defined as four or more identical traps occurring within a 30-second period. To be considered identical, an SNMP trap must meet three criteria: • • • Is from the same device—A device that has the same IPv4 address Has the same trap identifier—The same MIB trap Object ID (OID) Has the same number of variable string values—In the same order and with the same values If an SNMP trap storm does occur, then the first three traps are converted into alerts. After the third trap, OneView creates a trap storm event. Intermediate trap storm events will also be created to continue informing administrators about the issue.

B is correct!

Because if it is the correct one

B is correct, "Four or more identical SNMP traps have been logged within the past 30 seconds."

B is correct answer

Should be B as consensus below

it is B. Do they change it?

"An SNMP trap storm is defined as four or more identical traps occuring within a 30-second period."

From HPe website, the 30 second period seems to be important, and it mentions they need to be identical, so B would be my choice also