$(15)$ An office products distribution center receives $5$ orders as follows.

$\backslash$table$[[$Order #$,$SKU,Qty$],[1001,2"$ Notebook,$12],[,$Medium binder clip pack,$50],[,$Medium black stapler,$2],[1002,8\mathrm{.}5"$x$11"100-$page pads,$20],[,2"$ Notebook,$20],[1003,$Medium black stapler,$5],[,$Medium binder clip pack,$100],[,$Large binder clip pack,$50],[1004,$Wall clock,$1],[,$Safe,$1],[,$Label maker,$1],[1005,$Copier paper ream $($letter$),50],[,$Copier paper ream $($legal$),10],[,$Toner cartridge,$4]]$

a$.(5)$ How many lines total are there?

b$.(10)$ Items are picked by order pickers and placed into carts. An order picker travels from location to location picking all items in his list. Paper products $($including notebooks$)$ are stored in one zone. All other items are stored in another. Travel time between zones averages $2\mathrm{.}5$ minutes. Time to pick a line averages $30$ seconds. This includes travel from the previous item $($or entry into a zone$)$ to the one being picked plus the time to retrieve the item being picked $($quantity independent$).$ This is only for travel within a zone. If an order is picked separately, it takes $45$ seconds on average to merge its lines from the separate picker carts into the order to be shipped out. Should the WMS assign one picker to pick all items to his cart or two pickers to pick items $($one per zone$)$ and if needed merge items from each cart into orders afterward?