not able to use a variable for dropDown index in taiko

[dhananjey-oss]

Hi Team,
Im using the taiko dropDown api the following way and it is throwing error

await dropDown('Product').select({index:r});

where 'r' is actually declared this way....
for (var r of table.rows) {
.....
}
I want to read all the rows from the .csv file, hence declared a loop.

However, if I write the code in the below way, it works fine. But it is a single row.
await dropDown('Product').select({index:3});

Please help.