How do I get attributes of xml elements?

I'm trying to load an xml document to extract questions with answers and then store them in an array. To identify the correct answer, I use an attribute.

To get an attribute with xPath you use node/@attribute, however, whenever I log the result, I get a blank line.

xml snippet:

<questions>

<b0>

<quest>ex</quest>

<ans ok="0">1</ans>

<ans ok="0">2</ans>

<ans ok="0">3</ans>

<ans ok="1">good</ans>

</b0>

</questions>

event sheet example: