To generate higher profit margins, producers must work to
increase their total supply.
increase their total expenses.
decrease their customer base.
decrease their production costs.

decrease their production cost

Explanation:because decreasing their costs would mean they will use less money on their product and people will buy it more often

Decrease their production costs.

Explanation:

Profit margin is the ratio of gross profit to net sales expressed as a percentage. This measures how an entity is able to control its cost and can be used as inter-corporation comparison for entities in the same industry .

The cost of goods sold is subtracted from the net sales to obtain gross profit. The gross profit is in turn divided by the net sales and expressed as a percentage to obtain the profit margin.

When the cost of production is reduced or decreased, the gross profit which form the numerator of the profit margin fraction will increase and with an increase in the numerator the profit margin will go up, all things being equal.