The number of stems of Dahlia that can be purchased at $10 is 2. Option C
How many stems can be purchased for $10?
The graph shows;
Cost of stems in dollars on the y-axis
Number of stems on the x-axis
At the cost of $10, 2 stems of Dahlia is bought.
At the cost of $20, 4 stems of Dahlia is bought.
At the cost of $30, 6 stems of Dahlia is bought.
At the cost of $40, 8 stems of Dahlia is bought.
At the cost of $50, 10 stems of Dahlia is bought.
Therefore, the unit cost of stem = Cost / number of stems
= $20 / 4
= $5 per stem