Increases in the materials account are based on which are supported by

a. receiving reports; suppliers' invoices
b. receiving reports; materials requisitions
c. materials requisitions; receiving reports
d. suppliers' invoices; materials requisitions

a. receiving reports; suppliers' invoices

Explanation:

The materials account gets increased only when the material actually gets to the warehouse. That means that a receiving report has to be generated in order to increase the materials account. This document is backed up by a supplier invoice, which states the amount invoiced by our supplier (vendor) - the increase in our materials' value.

answer; im thinking customer:

answer; hazards;