Here is the answer: 
A reduction of 1.7% will mean that 98.3% will remain. 
so, reduction factor of 0.983/year 
=> A(t) = A(0) x (0.983)^t 
Then, after 6 years we have: 
A(6) = 4600 x (0.983)⁶ => 4150 
Therefore, the answer for this would be the third option. Hope this helps.