Cells membranes are a phospholipid bilayer, with the hydrophobic "tails" of the phospholipids oriented to the interior of the bilayer, and the hydrophilic "heads" to the exterior of the bilayer.
They are fluid, which means that other molecules in them, such as proteins, are not fixed in position. One of the components of the membrane in animal cells is cholesterol, which helps to give rigidity and strength to the membrane
The cell membrane is impermeable to ions and polar molecules, while hydrophobic molecules can pass by passive diffusion.
This means that only statement 2 is true (option b).