Answer :
The correct answer is:
1.65 billion.
Explanation:
Since the output is expected to decrease by 8.4%, this means we will have
100-8.4 = 91.6% of the output.
91.6% = 91.6/100 = 0.916
91.6% of 1.8 billion is then
0.916(1.8) = 1.6488 ≈ 1.65 billion