Amino acid substituted in sickle cell anaemia is

The correct option is D Valine for glutamic acid in beta chain

Sickle-cell disease is caused by a single point mutation (a missense mutation) in the beta-haemoglobin gene that converts a GAG codon into GUG, which encodes the amino acid valine rather than glutamic acid.

So, the correct answer is 'Valine for glutamic acid in a beta chain'.