How to select individual rows in a D3 table - d3.js

Question

Currently learning D3 and I'm a bit confused with tables. I was able to find this code in the internet which creates a simple HTML table:
function tabulate(data, columns) {
var table = d3.select("#container").append("table"),
thead = table.append("thead"),
tbody = table.append("tbody");
// append the header row
thead.append("tr")
.selectAll("th")
.data(columns)
.enter()
.append("th")
.text(function(column) { return column; });
// create a row for each object in the data
var rows = tbody.selectAll("tr")
.data(data)
.enter()
.append("tr");
// create a cell in each row for each column
var cells = rows.selectAll("td")
.data(function(row) {
return columns.map(function(column) {
return {column: column, value: row[column]};
});
})
.enter()
.append("td")
.text(function(d) { return d.value; });
return table;
}
And I have this as my JSON file:
[
{"name": "John", "age": 11},
{"name": "Jane", "age": 20},
{"name": "Robert", "age": 35},
{"name": "Meg", "age": 56},
{"name": "Ryan", "age": 80},
{"name": "Emma", "age": 11},
{"name": "Dale", "age": 20},
{"name": "Sam", "age": 35},
{"name": "Belle", "age": 56},
{"name": "Snow", "age": 80}
]
It's going to create a simple two-column table. Now my question is, how can I select individual rows? if I use selectAll ("tbody tr"), it will of course select all the rows. But if I use select("tbody tr"), it will only select the first one.
Please keep in mind that I'm a complete newbie at this. I learn mostly through reading and trial and error.