In how many ways can live boys and three girls sit in a row such that all boys sit together?

In how many ways can live boys and three girls sit in a row such that all boys sit together?

A. 4800
B. 5760
C. 2880
D. 15000
Explanation:
Treat all boys as one unit. Now there are four students and they can be arranged in 4! ways. Again five boys can be arranged among themselves in 5! ways.
Required number of arrangements = 4! * 5! = 24 * 120 = 2880.