Assuming concrete below the neutral axis to be cracked,

Assuming concrete below the neutral axis to be cracked, the shear stress across the depth of a singly-reinforce rectangular beam section

1. increases parabolic ally to the neutral axis and then drops suddenly to zero value
2. increases parabolic ally to the neutral axis and then remains constant over the remaining depth
3. increases linearly to the neutral axis and then remains constant up to the tension steel
4. increases parabolic ally to the neutral axis and then remains constant up to the tension steel

increases parabolic ally to the neutral axis and then remains constant up to the tension steel