If t denotes the thousandths digit in the decimal representation of d above, what digit is t?

a) if d were rounded to the nearest hundredth ,the result would be 0.44
b) if d were rounded to the nearest thousandth,the result would be 0.436

I have a doubt on b) i.e suppose if I consider two cases

Case 1: i take 0.43t3--------> in this case t will be 6 because 3 is less than 5
Case 2: I take 0.43t6--------> in this case t will be 5 because 6 is greater than 5 and when rounded off gets to 0.436............

how can answer be b) because I am getting two different values of t in above cases.........