The correct option is B Spores → Sporangia → Sporophylls → Strobili
Gymnosperms are heterosporous. i.e., produce two different kinds of spores–the male (microspores) and the female (megaspores). The spores are borne inside the sporangia. The two types of sporangia (microsporangia and megasporangia) are borne on special leaf-like structures called sporophylls, microsporophylls (= stamens) and megasporophylls (= carpels), respectively. The sporophylls are usually aggregated in the form of compact structures called cones or strobili. The cones are generally unisexual, i.e., the male cones are microsporangiate (pollen cones) and the female cones are microsporangiate (seed cones). Hence, the correct sequence is: Spores → Sporangia → Sporophylls → Strobili.