Use 0 as the value of headers

QUERY(data, query, [headers]) becomes QUERY(data, query, 0)

the default of -1 attempts to guess headers which may not be what you want.

See https://support.google.com/docs/answer/3093343?hl=en&sjid=4713053022561982617-AP#null

Rename the label

label Sum(D) ''

Instead of returning a label with the query use an empty string ''

For more information see https://developers.google.com/chart/interactive/docs/querylanguage#Label