Which of the following is not an antibiotic?

$.........$ is a potent vasodilator.

Which of the following is/are barbiturates?

Match the detergents given in Column-$I$ with their uses given in Column-$II$.

Column-$I$	Column-$II$
$(A)$ $[CH_{3}(CH_{2})_{15}N(CH_{3})_{3}]^{+}Br^{-}$	$(1)$ Dishwashing powder
$(B)$ $CH_{3}(CH_{2})_{11}-C_{6}H_{4}-SO_{3}^{-}Na^{+}$	$(2)$ Laundry soap
$(C)$ $C_{17}H_{35}COO^{-}Na^{+} + Na_{2}CO_{3} +$ Rosin	$(3)$ Hair conditioners
$(D)$ $CH_{3}(CH_{2})_{16}COO(CH_{2}CH_{2}O)_{n}CH_{2}CH_{2}OH$	$(4)$ Toothpaste

What are the functions performed by histamine in the body?

$A$ chemist has $4$ samples of artificial sweetener $A, B, C$,and $D$. To identify these samples,he performed certain experiments and noted the following observations:
$(i)$ $A$ and $D$ both form blue-violet colour with ninhydrin.
$(ii)$ Lassaigne extract of $C$ gives positive $AgNO_{3}$ test and negative $Fe_{4}[Fe(CN)_{6}]_{3}$ test.
$(iii)$ Lassaigne extract of $B$ and $D$ gives positive sodium nitroprusside test.
Based on these observations,which option is correct?