The wood with the least expensive price per unit length is A. Ash.
To determine the least expensive price per unit length, we need to calculate the cost per unit length for each type of wood. Given that 100 cm = 10 dm = 1 m, we can convert the lengths to a common unit (cm in this case) and then find the cost per unit length.
Here are the calculations:
Ash: $4.97 / 100 cm = $0.0497 per cm
Maple: $0.07 / 1 cm = $0.07 per cm
Oak: $15.99 / 200 cm = $0.07995 per cm
Walnut: $0.98 / 1 dm = $0.98 per dm (since 1 dm = 10 cm)
Now, we compare the prices:
A. Ash: $0.0497 per cm
B. Maple: $0.07 per cm
C. Oak: $0.07995 per cm
D. Walnut: $0.98 per dm (which is equivalent to $0.098 per cm)
Therefore, the wood with the least expensive price per unit length is A. Ash.