Suppose a person is born outside the US to US citizen parent(s) and meets all the requirements to be a US citizen. The person fulfills all the requirements, such as filing US tax returns and registering for selective service. But the person never enters the US, and the person's parents never physically reside in the US while the person is growing up. Neither the person nor the parents are in the US military and do not work for a federal or international agency.
Can the person vote in any US elections? If so, which jurisdiction would they request an absentee ballot from?
This is hypothetical; I'm not an ex-pat, I'm an election official.