You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: THE ELEMENTS 
Clue: Most fluorescent lights are filled with a combination of argon & this element, Kr
krypton

Category: THE COMPUTER AGE 
Clue: Dan Bricklin developed VISICALC, the first of these programs, similar to an accounting ledger
spreadsheet

Category: THE SOLOMON ISLANDS 
Clue: The main industries in the Solomons include mining, timber & fishing for this fish

tuna