Miles has owned a house in Honolulu, HI for $10$ years. He and his wife, Shivani, have lived there

together for six years. In $2023,$ Miles sells the house for $6,000,000.$ Miles originally paid

$1,230,000.$ If Shivani and Miles file a joint return, what is their: step by step

$($a$)$ Realized gain?

$($b$)$ Recognized gain?

$($c$)$ What if$,$ instead, Miles and Shivani have never lived together, but are married and file a

joint return. What is their recognized gain?