GraphQL Query and Gatsby - Populating Author Bio Raw Text

  query BlogPostTemplateQuery($id: String!) {
    post: sanityPost(id: { eq: $id }) {
      id
      publishedAt
      categories {
        _id
        title
      }
      mainImage {
        ...SanityImage
        alt
      }
      title
      slug {
        current
      }
      _rawExcerpt(resolveReferences: { maxDepth: 5 })
      _rawBody(resolveReferences: { maxDepth: 5 })
      authors {
        _key
        author {
          image {
            crop {
              _key
              _type
              top
              bottom
              left
              right
            }
            hotspot {
              _key
              _type
              x
              y
              height
              width
            }
            asset {
              _id
            }
          }
          name
          bio 
        }
      }
    }
  }
`;

There was an error in your GraphQL query:

Field "bio" of type "[SanityBlock]" must have a selection of subfields. Did you mean "bio { ... }"?