Consider the following key performance indicators, and classity each indicator according to the balanced scorecard perspective a addresses. Choose from the financlal perspective, customer perspective, internal business perspective, and the learning and growth perspective. $($fir there is only one perspective, leave the second field blank.$)$

Performance Indicator

Perspective$($s$)$

a$.$ Number of custorner complaints

b$.$ Number of information system upgrades completed

$$

$$

$$

$$

Residual income $$

$$

d$.$ New product development time $$

$$

$6.$ Employee turnover rate

$$

$$