Study the information below to answer these questions.
Seeta, Rajinder and Surinder are children of Mr and Mrs Aggarwal.
Renu, Raja and Sunil are children of Mrs and Mr Malhotra.
Sunil and Seeta are a married couple and Ashok and Sanjay are their children.
Geeta and Rakesh are children of Mr and Mrs Gupta.
Geeta is married to Surinder and has three children named Rita, Sonu and Raju.
What is Sanjay's surname?