(A) $(i)$ True: Hyperconjugation involves the delocalization of $\sigma$-electrons of a $C-H$ bond into an empty $p$-orbital of a carbocation.
$(ii)$ False: While resonance explains stability,the specific term for the delocalization involving $\sigma$-electrons in carbocations is hyperconjugation,not resonance (which typically refers to $\pi$-electron delocalization).
$(iii)$ False: Hyperconjugation is generally considered an electron-donating effect (often denoted as $+H$),but it is not classified as $(+)$ or $(-)$ in the same way as inductive or mesomeric effects.
$(iv)$ True: The mesomeric effect is classified as $(+M)$ (electron-donating) or $(-M)$ (electron-withdrawing) based on the direction of electron flow.