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Solution

Given,

Number of pipeline stages:

$k=4$

Number of data items:

$n=1000$

Stage delays are:

$150$ ns, $120$ ns, $160$ ns and $140$ ns

Register delay:

$5$ ns

In a pipeline, clock cycle time is decided by the slowest stage.

Slowest stage delay:

$160$ ns

So, pipeline clock cycle time is:

$160+5=165$ ns

Total time required for $n$ tasks in a $k$-stage pipeline is:

$(k+n-1)\times \text{Clock cycle time}$

$=(4+1000-1)\times 165$

$=1003\times 165$

$=165495$ ns

$=165.495\ \mu sec$

Numerically, this is approximately $165.5$.

So, according to the given options, the answer is $165.5$.