The correct answer is option 'C', which is the 80386SL.

The 80386SL is a portable device manufactured by Intel. Let's take a closer look at the different options to understand why the 80386SL is the correct answer.

a) 80386DX:
The 80386DX is a microprocessor introduced by Intel in 1985. It is a 32-bit processor and was the successor to the 80286. However, it is not a portable device. It is designed for desktop computers and not intended for mobile use.

b) 8087:
The 8087 is not a portable device either. It is a numeric coprocessor introduced by Intel in 1980. It was designed to work alongside the 8086 and 8088 processors to provide floating-point arithmetic capabilities. However, it is not a standalone portable device.

c) 80386SL:
The 80386SL is a low-power version of the 80386 microprocessor. It was specifically designed for portable devices such as laptops and notebooks. The 'SL' in its name stands for "Super Low power." It operates at lower voltages and consumes less power compared to the standard 80386 processors, making it suitable for battery-powered devices.

d) 80386SX:
The 80386SX is a cheaper and slower version of the 80386DX processor. It is also not a portable device. Like the 80386DX, it is designed for desktop computers and not intended for mobile use.

In summary, out of the given options, the 80386SL is the only portable device manufactured by Intel. It is designed for mobile use, specifically for laptops and notebooks, and operates at lower power levels to prolong battery life.