Consider the following statements pertaining to boundary layer on solid surfaces:
1. The boundary layer separation takes place if the pressure gradient is zero
2. The condition of boundary layer separation is $\left ( \frac{\delta u}{\delta y} \right )_{y=0}=0$
3. Boundary layer on a flat plate is laminar if the Reynolds number is less than 5 x 105. Which of the above statements is/are correct?
(a) 1,2 and 3 (b) 1 and 2 only
(c) 2 and 3 only (d) 1 and 3 only