Which quantity in eack pair is larger? Select the single best answer in each part.

Note: Reference the SI prefixes table for additional information.

Part $1$ of $4$

$9GL$

$9dL$

Part $2$ of $4$

$2Mg$

$2g$

Part $3$ of $4$

$1nm$

$1km$

Part $4$ of $4$

$4s$

$4cs$