Q.Plot the given four-variable truth table on a Karnaugh map. The inputs are $A,B,C,D$ and the output $Y$ is 1 for the input rows $0001,\;0101,\;0111,\;1110,\;1111$ and 0 for every other row. Enter 1s in the output-1 cells and identify the minterms.

Each truth-table row with $Y=1$ becomes a 1 in its minterm cell. The five output-1 rows here are $0001,0101,0111,1110,1111$, i.e. minterms $m_1,m_5,m_7,m_{14},m_{15}$. …

[!TLDR]

The five output-1 rows are $m_1,m_5,m_7,m_{14},m_{15}$; mark 1s there and 0 in the other eleven cells.

A four-variable map has $2^4=16$ cells, rows in Gray-code order $\overline{A}\,\overline{B},\;\overline{A}B,\;AB,\;A\overline{B}$ and columns $\overline{C}\,\overline{D},\;\overline{C}D,\;CD,\;C\overline{D}$. Converting each output-1 row to a minterm:

$0001\Rightarrow\overline{A}\,\overline{B}\,\overline{C}D=m_1$; $0101\Rightarrow\overline{A}B\overline{C}D=m_5$; $0111\Rightarrow\overline{A}BCD=m_7$; $1110\Rightarrow ABC\overline{D}=m_{14}$; $1111\Rightarrow ABCD=m_{15}$.