Change B with B0.
If it doesnt work, check this: How To Use Alert Message Templates in Grafana - #3 by melori.arellano
To refer to labels and values from the query add a new annotation to the alert like this. Name the annotation AlertValues.
{{ with $values }}
{{ range $k, $v := . }}
Location: {{$v.Labels.location}}
Variable: {{$v.Labels.variable}}
Alerting value: {{ $v }}
{{ end }}
{{ end }}
