Concept:Spelling errors often occur in words borrowed from Latin or Greek; 'consensus' is commonly misspelled as 'concensus'.Explanation:Step 1: Check each option for correct spelling.Step 2: 'Concensus' is wrong. The correct spelling is 'Consensus', meaning general agreement (सामान्य सहमति).Step 3: Example: The committee reached a consensus on the budget proposal.Step 4: The other options are correctly spelled. 'Persistent' means continuing firmly (दृढ़). 'Millennium' means a period of one thousand years (सहस्राब्दि). 'Occurrence' means an incident or event (घटना).Therefore, the incorrectly spelt word is 'Concensus'.Answer:Option A: Concensus