OpenCart default does not give option to sell the product like this. Product option combination let admin make special set of option where the user will select only particular option to buy a t-shirt. TMD OpenCart product combination enables the combination for the master product into various child combination in a single attempt. Thus it provides ease of storing a product with its different attributes at one go. You can find combination in your OpenCart product master as given below when you can enable the field to get started
Benefits of TMD Power Suite Product Combination Module for OpenCart: Admin can define any of the two properties related to a product from any industry. Create as many properties as per your needs. Use different product combination for different kinds of products. Best for online merchants dealing with various products. Compatible for apparels and footwear industry and other e-commerce trading businesses. Use a single master product to define all its child and its variant.