Statement 1
If d were rounded to the nearest hundredth, the result would be 0.44 this means the value of
$$t\ is\ge5\ and\ \le9$$
$$5\le t\le9$$
The value of t can either be 5, 6, 7, 8. or 9, information given is not enough to arrive at a specific value for digit t

Statement 2
If d were nearest to the nearest thousandth, the result would be 0.436.
d = 0.43t7
Since the value of t is greater or equal to 5, rounding to the nearest thousand will increase the thousand by place 1
$$d=0.43\left(t+1=6\right)7$$
$$d=0.43\left(t=6-1=5\right)7$$
$$d=0.4357$$
If it is rounded to the nearest thousandth
d=0.436
Therefore t = 5
Statement 2 alone is SUFFICIENT. $$Answer\ is\ Option\ B$$