Summer is a time for fun.Those coastal cities attract millions of tourists.Holiday-makers invade the seaside towns.； Which of the following is the best explanation of “invade” in the sentence？

Summer is a time for fun.Those coastal cities attract millions of tourists.Holiday-makers invade the seaside towns.； Which of the following is the best explanation of “invade” in the sentence？
A.intrude
B.enter into
C.flood into
D.stream down
正确答案：flood into