To solve this problem, we need to identify which plant group has a male gametophyte with the least number of cells. Let's analyze each option:$\newline \bullet$Pteris:$\newline$ - Pteris is a genus of ferns, which are pteridophytes.$\newline$ - In pteridophytes, the male gametophyte is typically multicellular, consisting of several cells.$\newline \bullet$Funaria:$\newline$ - Funaria is a genus of mosses, which are bryophytes.$\newline$ - In bryophytes, the male gametophyte is also multicellular, forming antheridia with multiple cells.$\newline \bullet$Lilium:$\newline$ - Lilium is a genus of flowering plants, which are angiosperms.$\newline$ - In angiosperms, the male gametophyte (pollen grain) is highly reduced, typically consisting of only 2 or 3 cells.$\newline \bullet$Pinus:$\newline$ - Pinus is a genus of gymnosperms.$\newline$ - In gymnosperms, the male gametophyte is more complex than in angiosperms, usually consisting of several cells.$\newline$Therefore, the male gametophyte with the least number of cells is found in Lilium, which is an angiosperm.$\newline$Thus, the correct option is Option 3.