The raised cosine pulse p(t) is used for zero ISI in digital communications. The expression for p(t) with unity roll-off factor is given by $$p\left( t \right) = \frac{{\sin 4\pi Wt}}{{4\pi Wt\left( {1 - 16{W^2}{t^2}} \right)}}.$$      The value of p(t) at $$t = \frac{1}{{4W}}$$  is

A. Only 800 Hz component B. 800 Hz and 900 Hz components C. 800 Hz and 1000 Hz components D. 800 Hz, 900 Hz and 100 Hz components

A. 4 MHz B. 8 MHz C. 8 GHz D. 8.004 GHz

A. Attenuation of high frequencies in reproduction B. Attenuation of low frequencies in reproduction C. Greater aliasing errors in reproduction. D. No harmful effects in reproduction

A. 16 Mbps B. 100 Mbps C. 600 Mbps D. 6.4 Gbps