Which of the following is not a chiral

[Step 1]:A carbon atom, tetrahedrally linked to four different monovalent atoms (or) groupsis called asymmetric carbon atom (*) and chiraloption (1)    CH3−CH2−C|BrH−CH2−CH3option (2)   CH3−C|OH*H−CH2−CH3option (3)   CH3−C|OH*H−COOHoption (4)   CH3−C|Br*H−C|Br*H−CH3Therefore options (2),(3) and(4) are chiral option (1) is not chiral due to two identical ethyl (C2H5) groups.