In which location does the UK government hold its sessions?

Westminster is the heart of the UK government because it's where the Houses of Parliament are located. Think of those iconic images of Big Ben and the Palace of Westminster – that's where the House of Commons and the House of Lords meet to debate and pass laws that affect the whole of the United Kingdom. This area has been a centre of English, and later British, governance for nearly a thousand years. Edward the Confessor had a palace built here in the 11th century, and Parliament has met here since the 13th century. So, when you think about the UK government holding its sessions, Westminster is the place to remember. The other options, Senedd, Holyrood, and Stormont, are all important legislative bodies, but they represent the devolved governments of Wales, Scotland, and Northern Ireland, respectively. They handle regional matters, but the main UK government, which makes laws for the entire country, sits in Westminster.
Just think of the famous Big Ben clock tower; it's located in Westminster - the same place where the UK government convenes.