Hello! The best answer would be C - Colds because bacteria can reproduce and spread rapidly, which is why a cold sometimes develops fast. As for the others, your body is just adjusting to the weather with A, B is a sexually transmitted disease which is caused from contact with another through sex, D is caused by sweets/certain foods that break down your teeth. I hope I helped you!! Have a great day!!
The answer is Paramecium.
The paramecium is a unicellular ciliated protozoan. They are
often found in fresh water and brackish water areas. They have the elongated
shaped that looks like a rod and has the color violet under the stain because it signifies that it is positive.
