No other nation can produce a book collector on quite the heroic scale of Sir Thomas Philips (1792-1872), who in 50 years amassed the greatest private library the world has ever seen, spending on it some £250,000 (add two noughts for inflation). Few other nations can produce such dedicated book loonies as Bernard Levin, who has been advised that should he ever be rash enough to display on shelves the tons of books he has amassed so far, he would assuredly bring the walls of his London apartment crashing about his ears.
Fill in the blank with the correct information from the passage:

Sir Thomas Philips in ________ years amassed the greatest private library.

1. A
   60
2. B
   40
3. C
   30
4. D
   50