Enable D3 under Libraries, wait until it is checked, then paste the whole editor. Write an SVG, bind arrays, console.log selection size.

Goal

Run every block and confirm the chart is visible.

document.body.innerHTML = '<div id="viz"></div>';
const svg = d3.select("#viz").append("svg").attr("width", 480).attr("height", 200);
svg.selectAll("circle").data([21, 15, 15, 18, 12]).join("circle")
  .attr("cx", (d, i) => 40 + i * 80).attr("cy", 100).attr("r", d => d / 2).attr("fill", "#1d4f7a");
console.log("circles", svg.selectAll("circle").size());

document.body.innerHTML = '<div id="viz"></div>';
console.log("d3 version", d3.version);