Competition: Last Chance To Win! The National Theatre Story

This week we’ve got a copy of The National Theatre Story to give away, courtesy of Oberon Books.
Daniel Rosenthal’s biography of our great theatrical institution on the South Bank was published to coincide with the 50th anniversary of the NT. Upon its publication, Michael Coveney in The Independent wrote:

“It's all here, summarised better than anywhere else…. this is a story with guts, great actors, laughter, disaster, and other properties that most books don't possess.”

The National Theatre Story is out now in hardback and costs £35 – but you can win a copy here. Simply answer the following question:
Who designed the National Theatre building on the South Bank? Was it:
a) Denys Lasdun b) Laurence Olivier c) The Duke of Rothesay
HINT:  Monday’s post, which featured a sound clip of Daniel Rosenthal reading from his book will give you a GREAT BIG CLUE ;) Catch up with that post HERE. 
(There's always a big clue on the Somewhere Else London Walk too!)
HOW TO ENTER: As usual, email your answer HERE.
The competition closes at midnight on Friday 21st February 2014 and the winner will be notified by email.
Visit the Oberon Books website at www.oberonbooks.com
Catch up with the London Walks London Theatre podcast HERE: 
A London Walk costs £9 – £7 concession. To join a London Walk, simply meet your guide at the designated tube station at the appointed time. Details of all London Walks can be found at www.walks.com.