Company A sells heaters and Company B sells air conditioners. Which is the safer investment, Company A

Question:

Company A sells heaters and Company B sells air conditioners. Which is the safer investment, Company A stock, Company B stock, or a containing half of each?
Portfolio
A portfolio is a grouping of financial assets such as stocks, bonds, commodities, currencies and cash equivalents, as well as their fund counterparts, including mutual, exchange-traded and closed funds. A portfolio can also consist of non-publicly...