Consider 4-bit gray code representation of numbers. Let h<sub>3</sub> h<sub>2</sub> h<sub>1</sub> h<sub>0</sub> be the gray code representation of a number n and g<sub>1</sub>g<sub>2</sub>g<sub>3</sub>g<sub>0</sub> be the gray code representation of the number (n + 1) modulo 16. Which one of the following functions is correct?
(A) g<sub>0</sub> (h<sub>3</sub> h<sub>2</sub> h<sub>1</sub> h<sub>0</sub>) = Σ(1,2,3,6,10,13,14,15)
(B) g<sub>1 </sub>(h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em;font-size:10.5px;">3</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em;font-size:10.5px;">2</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em;font-size:10.5px;">1</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em;font-size:10.5px;">0</span>) = Σ(4,9,10,11,12,13,14,15)
(C) g<sub>2</sub> (h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">3</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">2</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">1</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">0</span>) = Σ(2,4,5,6,7,12,13,15)
(D) g<sub>3</sub> (h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">3</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">2</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">1</span> h<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em; font-size:10.5px;">0</span>) = Σ(0,1,6,7,10,11,12,13)