Which of the following companies started selling Humulin in $1983$?

$(x^2+y^2) dy = xy dx$. If $y(x_0) = e$ and $y(1) = 1$,then the value of $x_0$ is equal to

The work functions for metals $A, B$ and $C$ are respectively $1.92\, eV$,$2.0\, eV$ and $5\, eV$. According to Einstein's photoelectric equation,the metals which will emit photoelectrons for a radiation of wavelength $4100\, \mathring{A}$ is/are:

$\lim _{x \rightarrow 0} \frac{\sin \left(\pi \cos ^2 x\right)}{x^2}$ is equal to

The angle between a pair of tangents drawn from a point $P$ to the circle $x^{2}+y^{2}+4x-6y+9 \sin^{2} \alpha + 13 \cos^{2} \alpha = 0$ is $2 \alpha$. The equation of the locus of the point $P$ is

For retting of jute,the fermenting microbe used is: