Answer: b dangler
Step-by-step explanation:
A dangler is a modifier or participle that does not connect correctly to the rest of the sentence. It is a sentence element that doesn’t relate syntactically to what it’s intended to modify. In this case When packing the order yesterday, one important item was omitted the subject of packing is not the same of
was omitted. The present participial phrase at the beginning of the sentence does not connect to main the main clause.
The correct option would have been :
When packing the order yesterday, I omitted one important item
or
One important item item was omitted when being packed