In the following passage some words have been deleted. Fill in the blanks with the help of the alternatives given. Select the most appropriate option for each blank.

Comprehension:
Big Ben is the UK’s most iconic symbol. Since 2017, the Elizabeth Tower and the bell inside have been (1) ______ renovation. The structure is 160 years old and (2) ______ regular maintenance. (3) ______ many years, people had been painting the hands and numbers (4) ______ the clock black, but last Thursday, the workers (5) ______ the clock’s original colour, Prussian Blue!