Mom and dad and two kids have to get across the river,and they found a boat,but it is so small it can carry only 1 adult or two kids. luckily both the kids are good rowers,but how can the whole family get across the river.(hint : one or two kids can ride the boat

2 kids cross, one brings the boat back, one parent crosses, the other kid brings the boat back, both kids cross again, one kid brings the boat back, other parent crosses, the other kid brings the boat back, both kids cross again, one kid brings the boat back, the fisherman crosses, the other kid brings the boat back, both kids cross again. the fisher man is on the side where the kids and parents are. he can take the boat. total trips 11.

it's the second one because the first has 2 over x which can't be a polynomial because it can't have a variable on the bottom same thing with the last one and the 3rd one it have a x in the square root sign