How many alkane of molecular weight 100 are chiral?

An alkane of molecular weight 86 g/mol on monochlorination gives two products. The alkane is

An alkane of molecular weight 86 g/mol on monochlorination gives two products. The alkane is

An alkane by molecular weight 72 upon chlorination gives one monochlorination product. The alkane is

An alkane by molecular weight 72 upon chlorination gives one monochlorination product. The alkane is

The optically active alkane of lowest molecular mass which is also chiral is-

What is the molecular formula for the alkane of smallest molecular weight which possesses a stereogenic centre?