Border _____ between the two countries are on the rise.[A] accident [B] incidents [C] events [D] occurrences为什么选C?请翻译句子

Border _____ between the two countries are on the rise.
[A] accident [B] incidents [C] events [D] occurrences
为什么选C?请翻译句子

C
EVENT 指的是（国家）重大事件
BODER EVENT 是指边境问题
整句意思是两国的边境问题不断升级