code
{sites.map((site) => (
<option value="{site.SiteId}">{site.SiteName}</option>
))}
result
code
{sites.map((site) => (
<option value="{site.SiteId}">{site.SiteName}</option>
))}
result
No quotes around such attributes
<option value={site.SiteId}>{site.SiteName}</option>