Which of the following comes under the category of random errors?

$A$ physical quantity $x$ is calculated from the relation $x = \frac{a^2 b^3}{c \sqrt{d}}$. If the percentage errors in $a, b, c,$ and $d$ are $2\%, 1\%, 3\%,$ and $4\%$ respectively,what is the percentage error in $x$?

The length $l$,breadth $b$,and thickness $t$ of a block of wood were measured with the help of a measuring scale. The results with permissible errors are $l = 15.12 \pm 0.01 \; cm$,$b = 10.15 \pm 0.01 \; cm$,and $t = 5.28 \pm 0.01 \; cm$. The percentage error in volume up to proper significant figures is: (in $\%$)

$A$ body travels uniformly a distance of $(13.8 \pm 0.2) \ m$ in a time $(4.0 \pm 0.3) \ s$. The velocity of the body within error limits is

If potential $V = 100 \pm 0.5\,V$ and current $I = 10 \pm 0.2\,A$ are given,what will be the value of resistance?

Three students $S_{1}, S_{2}$ and $S_{3}$ perform an experiment for determining the acceleration due to gravity $(g)$ using a simple pendulum. They use different lengths of pendulum and record time for different number of oscillations. The observations are as shown in the table.

Student No.	Length of pendulum $(cm)$	No. of oscillations $(n)$	Total time for oscillations $(s)$	Time period $(s)$
$1.$	$64.0$	$8$	$128.0$	$16.0$
$2.$	$64.0$	$4$	$64.0$	$16.0$
$3.$	$20.0$	$4$	$36.0$	$9.0$

(Least count of length $= 0.1 \, cm$,least count for time $= 0.1 \, s$)
If $E_{1}, E_{2}$ and $E_{3}$ are the percentage errors in $g$ for students $1, 2$ and $3$ respectively,then the minimum percentage error is obtained by student no. ....... .