Final answer:
A bank assumes a financial obligation in export financing with both a Letter of Credit (L/C) and a documentary collection.
Step-by-step explanation:
In the form of export financing, a bank assumes a financial obligation in option E) with both a Letter of Credit (L/C) and a documentary collection. Both forms involve the bank providing financial assurance to the exporter and assuming the responsibility of ensuring that payment is made by the importer.