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.

Tourism is one (1)______ the biggest businesses in the world, generating (2)______ 200 million jobs. It is vital for the economies of (3)______ countries. The downside is that tourism is a major (4)______ of climate change through the carbon (5)______ it causes.

Q:

Select the most appropriate option to fill in blank number (2).

• 1
  at most
• 2
  at least
• 3
  at much
• 4
  at last