This is a robotic call source, purporting to be collecting funds for "homeless veterans." How you respond determines what phrases are played back to you next. It's all automated. If they think you are not a good prospect, the call will hang up. These are crooks.
If you answer, "Hello?", you will get one robotic message. If you don't answer, you will get another. This is computerized and no human is involved.
They are not legitimate charities. Ask them for their IRS form 990 if you doubt me. Call 844 279-6505 and ask for IRS Form 990. They will not respond, as they are crooks.