The logic circuit shown below has the input waveforms $A$ and $B$ as shown. Pick out the correct output waveform.

Dispersive power depends on the following:

The instantaneous angular position of a point on a rotating wheel is given by the equation $\theta(t) = 2t^3 - 6t^2$. The torque on the wheel becomes zero at $t = $ ....... $\text{sec}$.

Match the following columns and select the correct option:

$(a)$ Eosinophils	$(i)$ Immune response
$(b)$ Basophils	$(ii)$ Phagocytosis
$(c)$ Neutrophils	$(iii)$ Release histaminase enzyme
$(d)$ Lymphocytes	$(iv)$ Release granules containing histamine

$(a)\quad (b)\quad (c)\quad (d)$

$(a+b) \cdot (b+c) \times (a+b+c)$ is equal to